The role of Customary Law in International Criminal Law″ based on Ntaganda Case Study.

3560A01Peeler2020F1 xResearchEssay1 TheroleofCustomaryLawinInternationalCriminalLaw1 x

The role of Customary Law in International Criminal Law″ based on Ntaganda Case Study. 

General Information

Course Number: POLS 3560

Course Title: Politics of International Law

Section: A0

1

Instructor: Dr. Bryan Peeler

CRN: 20048

Office: 527 Fletcher Argue Bldg.

Credit Hours: 3

Phone: (204) 272-1586

Term: Fall

Email: bryan.peeler@umanitoba.ca

Location of Class: Online via Webex

Office Hours: 2:30–3:30 M and appt.

Time of Class: 11:30-2:15 M

Objectives and Content

An introduction to international law including sources of international law, the use of force and international human rights

Required Readings

Scott, Shirley V., International Law in World Politics: An Introduction, 3rd. ed. (Boulder CO: Lynne Rienner Publishers, 2017).

Additional readings will be provided via UMLearn:

https://universityofmanitoba.desire2learn.com

Recommended Readings

Any recommended readings will be posted via the course UMLearn site.

Evaluation

Class participation, 20%

The class participation grade will be based on the following criteria:

· Your willingness to engage in constructive and respectful discussions (10/20)

· Evidence that you have completed and understood the assigned readings (10/20)

I will email you a report explaining on your participation grade at the end of term.

Research essay, Nov. 23: 40%

Students will submit a research essay intended to make an original argument and contribution to the existing literature on international law. You can write on a topic of your choice, provided that the paper touches on issues discussed in class and I have given my approval.

The research paper should be 4 to 5 pages in length. Your argument should rely on research published in academic or policy journals and government or think tank reports. You should try to write the papers in a concise, learned style that avoids jargon. Accordingly, the paper should be written in a way that entices the reader and contributes to our understanding of international law. See the essay guidelines for further information about the assignment

The essay will be graded according to the following criteria:

· Argument structure and flow (20/40)

· Depth, breadth, and originality of the analysis (10/40)

· Research and sources (5/40)

· Style, spelling, and grammar (5/40)

Your essay must be uploaded to UMLearn by 11:30am of the due date. Late papers will be penalized one grade fragment per day, including weekends and holidays.

1

1

Introduction

Customary law refers to the laws, customs and practices of the indigenous people or

communities. The Charter of the United Nations has annexed the statute of the Permanent

Court of International Justice by requiring it to decide disputes in accordance with

international law while at the same time considering the international custom (Diala, 2017).

The customary law is an instrumental source of applicable law in International Criminal

Court, but it comes secondary to the written rules of the Rome Statutes, Elements of Crimes,

and the Rules of Procedure and Evidence. This shows that despite being a secondary source

of applicable law for international law, customary law is still part of the fundamental

framework of international law (Petersen, 2017). Customary international law is a

fundamental consideration for the national and international courts especially when they are

faced with universal problems such as human rights violations, boundary disputes and even

trade. The custom law co-exists with treaties in the codification of international law and play

an instrumental role in governing areas that are not governed by the treaty law or rules. This

paper will seek to assess the application of customary law in international law and its core

roles in various aspects of application and the codification of the internationally recognized

legal framework.

Application of Customary Law in International Law

Deleted: The role of Customary Law in International
Criminal Law…

Commented [BP2]: Better: Customary international law is
made up of rules that derive from “a general practice accepted
as law.”

Deleted: Customary law is based on the life and customs of
a particular country or community.

Deleted: c

Commented [BP3]: Is this the correct term to use here?

Commented [BP4]: Chicago style footnotes are required as
per the Essay Guidelines.

Deleted: continues to be

Commented [BP5]: But no one thinks it isn’t a
“fundamental consideration.”

Commented [BP6]: You only have 8-10 pages so it would
be better to consider the application of CIL in a particular
area of IL When we talk you said you were going to write
about war crimes. You want to work that topic into your
introduction.

2

International law cannot ignore the existence of customary law in that they are both

continuously and co-actively influencing each other. The state practice and the opinio juris

(also referred to as the two-element approach) are important attributes that can be considered

in assessing how the customary law influence international law practice and

conceptualization (Petersen, 2017). Recently, the International Law Commission adopted the

two-element approach which is concerned with the general practice and accepted as law

elements that contributes towards customary international law. According to Article 38 of the

International Court of Justice, judicial decisions and teachings which are mostly qualified by

the publicists of the different countries can be an instrumental source of international law at a

subsidiary level.

The existence of international law has been associated with various customary

practices and formation of international treaties between states. For decades now, nations

have been able to develop the sovereignty principle to express authority over territory by

developing meaning in legal practices to ensure that their consensus in authority. In practice

of international law, it controls the relation between states. For example, as nationals relate to

each other, the existence of the rule of law and policies emanated from the nations’ free will

to accept and establish principles. This is to regulate the associations between the co-existing

nations along with the object to the achievement of similar objectives.

Among such achievements by independent nations, international law has aided in

enshrining standards, conventions, and treaties through the United Nations. As shown in

Article 2 of the United Nations Charter, it confirms the functions and importance of

international law as a guiding principle for the equality of member states, non-intervention

principle, and guide to the prohibition of application of force (Fox et al., 2017). Over recent

years, we have seen international law in application in the prohibition of excessive use of

Commented [BP7]: Good – cite thew ICL document.
Deleted: has

Deleted: states

Commented [BP8]: Not sure what you are trying to say
here and in the last sentence of the paragraph.

Deleted: ensure

Commented [BP9]: How does it do that? Cite Article 2 of
the Charter at this point – rather than a secondary source – to
provide evidence for your claim.

3

force to foster peace in events where the United Nations Security Council has authorized such

sanctions.

Additionally, the core guidelines and principles of international law have promoted

the advancement of human rights through the “Universal Declaration of Human Rights”

outlined in the U.N. Charter (Waltz, 2001). Although the principles of international law tend

to pool tension, other treaties have been formed to strengthen its role in ensuring that there is

sovereignty since the incidences of World Wars (Davidson, 2019). In its practice,

international law has supported the protection of human rights by ensuring that other

regulations are followed to ensure the protection of human rights. Overall, international law

has aided in the achievement of great developments by becoming central to the promotion of

political, social, and economic growth critical in advancing international security and peace.

The Prosecutor v. Bosco Ntaganda Application in Understanding how Customary Law

Enriches the International Law

The application of customary law to international criminal law is a subject that has

been questioned. The rules involved are vague and imprecise. The legality principle demands

the punishment and prosecution have clear international law provisions during criminal

actions (Fox et al., 2017). The distinction between customs and treaties in legal certainty is a

crucial subject. Treaties are rejected as International Criminal Law (ICL) sources where the

customs are deemed vague, a concept that is not accepted. The legality principle limits the

interpretation of the customary law. Customary law should instead be considered

international law sources (Pocar, 2020). They also help to interpret the written rules as a

model of ICL. The Criminal Tribunal for the former Yugoslavia (ICTY) fails to specify the

law applicable. The secretary general of the UN stated that the tribunal use international

humanitarian rules that are in line with the customary law. The action was meant to limit

Commented [BP10]: What does this mean?

Commented [BP11]: Of CIL or international criminal law?
You need to be more careful in your writing.

4

ICTY from acting upon customary law crimes hence advocating for legality principle Pocar,

F. (2020). The ICTY appealing section implemented customary laws criminalizing the

damages in war crimes. The Joint Criminal Enterprises (JCE) is also required to use

customary laws (Konderla, 2018). The international tribunals also use customary laws in their

jurisprudence. During the IMT, custom laws were applied to address the jurisdiction

challenge involved.

According to the Statute’s Article 21(1), customary law should be used as subordinate

sources of law by the ICC. The customary laws are used in addition to the rules of evidence

and procedure, crime elements and Rome Statute (Konderla, 2018). The customary laws are

crucial in determining various cases in the ICC framework. In the presence of a legal gap in

the written policies of ICC, customary laws may be used in the interpretation. During the

interpretation of the Ntaganda criminal case about crimes against humanity, the chamber of

pre-trial required ICTY cases to make interpretations in accordance with customary laws

(Tan, 2018). The Ntaganda case demands caution. When providing clarity for the war victims

of abusive slavery and rape, the Ntaganda trial chamber demanded more support of the Rome

Statute in providing the status need (Svaček, 2017). Customary law was considered where the

chamber demanded to know whether it required status limitation for the victims. The

prosecutor disputed the notion and sought for additional element on international law

framework. The prosecutor further argued that according to Statute’s Article 8, customary

laws should not be applied without a gap. The argument was rejected by the ICC appeals

chamber that argued in consistent with Article 8 of global humanitarian law. The rule allows

ICC to use the international customary law in spite of the lacuna in its existence. In dealing

with war crimes like the Ntaganda case, the ICC can use restrictive customary law elements

without a legal gap.

Commented [BP12]: How does this relate to the ICTY? I
can’t follow what you are trying to do with this paragraph.

Commented [BP13]: Which statute? The ICJ, the Rome
Statute, the ICTY?

Commented [BP14]: Are you trying to say that gaps in the
law allow for judges to apply their interpretation to cases?

Deleted: L

5

ILC considered the addition of customary law crimes when implementing the Rome

Statute. The action would help to determine cases that are beyond the legal chamber and

require further interpretation from a customary perspective. The Rome statute executes

jurisdiction in accordance with the customary law as provided by articles 24(1), 13(b), and

11(2) of the Statute. The ICC applied this notion when dealing with the Ntaganda case that

involved crimes against humanity. The Statute’s Article 12(3) allows the state parties to

accept the jurisdiction of ICC in consideration of customary law. According with article

13(b), the ICC is empowered to use Rome Statute over non-Rome States. The Jurisdiction

will demand the application of the customary law for example in the case of Ntaganda (Tan,

2018). The ICC-01/04-02/06 was the ICC case of Bosco who committed crimes against

humanity in his country.

Application of International Law and Customary Law in Upholding Human Rights

Customary law is a primary source of international law and the latter cannot be

conceived without customary law. The international law’s most fundamental concepts are

sourced from the customary law and one cannot talk about (?) the validity of the

international law without evoking the customary law. This is because the principles such as

pacta sunt servanda and bona fides which are crucial in the standing of international law are

primarily customary. Thus, international law is influenced by customary law due to the

opinio juris requirement which require the state’s behavior and decisions to also have a

psychological paradigm that helps to make states subjects of international law. As such,

through opinio juris states and their people can be convinced that they are subject to the

existing international law (Klein, 1988). The international customary law has played an

instrumental role in securing human rights through the international treaties which are ratified

by individual states law making organs making the human rights provisions binding

Commented [BP15]: Are you trying to say that the ILC
was trying to consider which war crimes could be considered
grounded n CIL? It’s very hard to follow the reason in your
paper.

Deleted: argue on

Commented [BP16]: This isn’t so much influence as it is a
definition of CIL. Opinio juris and state practice are what we
look at to see if a rule of CIL exists.

6

(Bassiouni, 1982). As such, international treaties have been a crucial source of international

law which is commonly used by the International Criminal Court to prosecute cases of human

rights abuse at an international scope.

The international custom as a source of international law and its ability to secure

human rights paradigms internationally can be found through diplomatic correspondence,

press releases, executive decisions, government comments on drafts that are created by the

international law commission and the official manuals on the legal questions. More

importantly, the activities of the international organs such as the United Nations General

Assembly have led to the adoption of international custom which eventually contributes to

the creation and expansion of the international law on human rights, trade and even

environmental regulations. Populism is increasingly facilitating the use of customary law in

human rights based cases that are conducted according to the principles of international laws

(Hostovsky Brandes, 2019). The ability of the international law in securing human rights and

other key aspects of importance such as environment and trade is its ability to bind states

even those that are yet to consent to the rules. Whereas international treaties are only bound

to those that have consented to them the customary law does not require any consent which

makes it an effective tool for advancing human rights principles.

Opposition of Customary Law Application in International Law

At the same time, there has been significant objections? contest against the use of

customary law in international law in international criminal law. This is because the rules

which are derived from the customary law are imprecise and at times vague in nature. The

application of customary law in international law can therefore be contested due to the

principle of legality which requires high specificity and legal certainty. At the same time,

customary law application as a source of international law can be supported by the argument

Commented [BP17]: Can you give example? When you
use a phrase like tis you want to cite examples.

Commented [BP18]: I not following you here. Can you
provide examples?

Commented [BP19]: When you use a phrase like this, cite
some sources who make such an objection.

7

that the principle of legality only requires the prosecution and punishment to be based on

clear provisions of international law when a crime was committed (Petersen, 2017). One

support of the application of customary law in the international law is the International

Criminal Tribunal for the former Yugoslavia which requires rules of international

humanitarian law to be beyond doubt and to be part of the customary law. Overall, the

primary role of the customary law in international law is to fill the legal gaps which

complicate the proceedings of the international law. As such, the customary law helps to

interpret the International Criminal Court’s written rules (Petersen, 2017). At different times,

the ICC has invoked Article 21 (1) (b) and to some extent confirmed customary law

especially in proceeds of cases that involves crimes against humanity.

Conclusion

It is evident that the customary law is widely accepted as a secondary source of

international law and helps in the interpretation of international law. At large, the two-

element approach such as in the case of The Prosecutor v. Bosco Ntaganda shows the

continued support and application of customary law in helping define and resolve the legal

gaps in the interpretation of the international law during key criminal proceedings. The

evidence of opinio juris is highly accepted in expounding how customary law can be used to

understand some cases at the international level. The customary law despite the existence of

ambiguity will continue to shape how international law is applied by the ICC in ruling

fundamental cases especially those that challenge the existing customs and values of the

different communities.

Commented [BP20]: This is the issue you want to base
your paper around. The principle of legality requires that a
specific law exists in order to charge someone with a crime.
The worry with international criminal law and prosecution for
war crimes is that these laws doesn’t exist. CIL is a possible
solution to this problem. But one worry is – as you point out
– there is a vagueness to CIL. You want to use the Ntaganda
case to explain this issue and maybe propose a solution.

Commented [BP21]: Argument: There is no clear thesis
statement or research question for the paper. While an attempt
is made to draw meaningful connection between these raised
in the course and the argument, the lack of a clear argument
makes the paper quite hard to follow. The material cites tends
to be used as a substitute for your own argument about CIL
and war crimes. 11/20

Analysis: Some awareness of different approaches to the
issue of CIL and war crimes and paper does attempt to
engage with issues raised in the course. 6.5/10

Research: The argument and analysis are located within a
good range of outside material but the is little critical
evaluation of the sources in the context of the argument.
3.25/5

Writing: Paper is very hard to read with frequent grammatical
errors. 2.75/5

23.5/40

8

Deleted: References¶
Bassiouni, M. C. (1982). The proscribing function of
international criminal law in the processes of international
protection of human rights. Yale J. World Pub. Ord., 9, 193.¶
Davidson L. (2019). The Importance of International Law. In:
Essays Reflecting the Art of Political and Social Analysis.
Critical Political Theory and Radical Practice. Palgrave
Macmillan, Cham. https://doi.org/10.1007/978-3-319-98005-
8_3¶
Diala, A. C. (2017). The concept of living customary law: a
critique. The Journal of Legal Pluralism and Unofficial
Law, 49(2), 143-165.¶
Fox, G. H., Boon, K. E., & Jenkins, I. (2017). The
Contributions of United Nations Security Council Resolutions
to the Law of Non-International Armed Conflict: New
Evidence of Customary International Law. Am. UL Rev., 67,
649.¶
Hostovsky Brandes, T. (2019). International law in domestic
courts in an era of populism. International Journal of
Constitutional Law, 17(2), 576-596.¶
Klein, D. F. (1988). A Theory for the Application of the
Customary International Law of Human Rights by Domestic
Courts. Yale J. Int’l L., 13, 332.¶
Petersen, N. (2017). The International Court of Justice and
the judicial politics of identifying customary international
law. European Journal of International Law, 28(2), 357-385.¶
Pocar, F. (2020). Returning to Customary Law. In The
International Criminal Court: Contemporary Challenges and
Reform Proposals (pp. 298-302). Brill Nijhoff.!
Konderla, J. (2018). International Customary Law in the
Jurisprudence of the ICTY and the ICTR. Wroclaw Review of
Law, Administration & Economics, 8(2), 287-300.¶
Svaček, O. (2017). Brothers and Sisters in Arms As Victims
of War Crimes: Ntaganda Case Before the ICC. Czech
Yearbook of Public and Private International Law, 8(1), 346-
357.¶
Tan, Y. (2018). The Identification of Customary Rules in
International Criminal Law. Utrecht J. Int’l & Eur. L., 34, 92.¶
U.N. International Law and Justice. Un.org. Retrieved from
https://www.un.org/en/sections/issues-depth/international-
law-and-justice/.¶
Waltz, S. (2001). Universalizing human rights: The role of
small states in the construction of the universal declaration of
human rights. Hum. Rts. Q., 23, 44.¶

2

2

The role of Customary Law in International Criminal Law

Student’s Name

Institutional Affiliation

The role of Customary Law in International Criminal Law

Introduction

Customary law refers to the laws, customs and practices of the indigenous people or communities. Customary law is based on the life and customs of a particular country or community. The charter of the United Nations has annexed the statute of the Permanent Court of International Justice by requiring it to decide disputes in accordance to the international law while at the same time considering the international custom (Diala, 2017). The customary law is an instrumental source of applicable law in International Criminal Court but it comes secondary after the written rules of the Rome Statutes, Elements of Crimes, and the Rules of Procedure and Evidence. This shows that despite being a secondary source of applicable law for international law customary law is still part of the fundamental framework of international law (Petersen, 2017). Customary international law continues to be a fundamental consideration for the national and international courts especially when they are faced by universal problems such as human rights violations, boundary disputes and even trade. The custom law co-exists with treaties in the codification of the international law and play an instrumental role in governing areas that are not governed by the treaty law or rules.
This paper will seek to assess the application of the customary law in international law and its core roles in different aspects of application and the codification of the internationally recognized legal framework.

Application of Customary Law in International Law

International law cannot ignore the existence of customary law in that they are both continuously and co-actingly influencing each other. The state practice and the opinio juris (also referred to as the two-element approach) are important attributes that can be considered in assessing how the customary law influence the international law practice and conceptualization (Petersen, 2017). Recently, the International Law Commission has adopted the two-element approach which is concerned with the general practice and accepted as law elements which contributes towards customary international law. According to the Article 38 of the International Court of Justice, judicial decisions and teachings which are mostly qualified by the publicists of the different countries can be an instrumental source of international law at a subsidiary level.

The existence of international law has been associated to various customary practices, and formation of international treaties between states. For decades now, nations have been able to develop the sovereignty principle to express authority over states by developing meaning in legal practices to ensure that their consensus in authority. In practice of international law, it controls the relation between states. For example, as nationals relate to each other, the existence of the rule of law and policies emanated from the nations’ free will to accept and establish principles. This is so as to regulate the associations between the co-existing nations along with the object to ensure achieve similar objectives.

Among such achievements by independent nations, international law has aided in enshrining standards, conventions, and treaties through the United Nations. As shown in Article 2 of the United Nation Charter, it confirms on the functions and importance of international law as a guiding principle for the equality of member states, non-intervention principle, and guide to prohibition of application of force (Fox et al., 2017). Over the recent years, we have seen international law in application in the prohibition of excessive use of force to foster peace in events where the United Nations Security Council has authorized such sanctions.

Additionally, the core guidelines and principles of international law have promoted the advancement of human rights through the “Universal Declaration of Human Rights” outlined in the U.N. Charter (Waltz, 2001). Although the principles of international law tend to pool tension, other treaties have been formed to strengthen its role in ensuring that there is sovereignty since incidences of World Wars (Davidson, 2019). In its practice, the international law has supported the protection of human rights by ensuring that other regulations are followed to ensure protection of human rights. Overall, international law has aided in the achievement of great developments by becoming central to the promotion of political, social, and economic growth critical in advancing international security and peace.

The Prosecutor v. Bosco Ntaganda Application in Understanding how Customary Law Enriches the International Law

The application of customary law to the international criminal law is a subject that has been questioned. The rules involved are vague and imprecise. The legality principle demands the punishment and prosecution to have clear international law provisions during the criminal actions (Fox et al., 2017). The distinction between customs and treaties in legal certainty is a crucial subject. Treaties are rejected as International Criminal Law (ICL) sources where the customs are deemed vague, a concept that is not accepted. The legality principle limits the interpretation of the customary law. Customary law should instead be considered international law sources (Pocar, 2020). They also help to interpret the written rules as a model of ICL. The Criminal Tribunal for the former Yugoslavia (ICTY) fails to specify the law applicable. The secretary general of the UN stated that the tribunal use international humanitarian rules that are in line with the customary law. The action was meant to limit ICTY from acting upon customary law crimes hence advocating for legality principle Pocar, F. (2020). The ICTY appealing section implemented customary laws criminalizing the damages in war crimes. The Joint Criminal Enterprises (JCE) is also required to use customary laws (Konderla, 2018). The international tribunals also use customary laws in their jurisprudence. During the IMT, custom laws were applied to address the jurisdiction challenge involved.

According to Statute’s Article 21(1), customary law should be used as subordinate sources of law by the ICC. The customary laws are used in addition to the rules of evidence and procedure, crime elements and Rome Statute (Konderla, 2018). The customary laws are crucial in determining various cases in the ICC framework. In the presence of legal gap in the written policies of ICC, customary laws may be used in the interpretation. During the interpretation Ntaganda criminal case against humanity, the chamber of pre-trial required ICTY cases to make interpretation in accordance to the customary laws (Tan, 2018). The Ntaganda case demands caution. When providing clarity for the war victims of abusive slavery and rape, the Ntaganda trial chamber demanded more support of the Rome Statute in providing the status need (Svaček, 2017). Customary law was considered where the chamber demanded to know whether it required status limitation for the victims. The prosecutor disputed the notion and sought for additional element on international law framework. The prosecutor further argued that according to Statute’s Article 8, customary laws should not be applied without a gap. The argument was rejected by the ICC appeals chamber that argued in consistent with the Article 8 global humanitarian law. The rule allows ICC to use the international customary law in spite of the Lacuna existence. In dealing with war crimes like the Ntaganda case, the ICC can use restrictive customary law elements without legal gap.

ILC considered the addition of customary law crimes when implementing the Rome Statute. The action would help to determine cases that are beyond the legal chamber and require further interpretation in customary perspective. The Rome statute executes jurisdiction in accordance to the customary law as provided by article 24(1), 13(b), and 11(2) of the Statute. The ICC applied this notion when dealing with the Ntaganda case that involved crimes against humanity. The Statute’s article 12(3) allows the state parties to accept the jurisdiction of ICC in consideration of customary law. According to the article 13(b), the ICC is empowered to use Rome Statute over non-Rome States. The Jurisdiction will demand the application of the customary law for example in the case of Ntaganda (Tan, 2018). The ICC-01/04-02/06 was the ICC case of Bosco who committed crimes against humanity in his country.

Application of International Law and Customary Law in Upholding Human Rights

Customary law is a primary source of international law and the latter cannot be conceived without customary law. The international law most fundamental concepts are sourced from the customary law and one cannot argue on the validity of the international law without evoking the customary law. This is because the principles such as pacta sunt servanda and bona fides which are crucial in the standing of international law are primarily customary. Thus, the international law is influenced by the customary law due to the opinio juris requirement which require the states behavior and decisions to also have a psychological paradigm which helps to make states subjects of the international law. As such, through opinio juris states and their people can be convinced that they are subject to the existing international law (Klein, 1988). The international customary law has played an instrumental role towards securing human rights through the international treaties which are ratified by individual states law making organs making the human rights provisions binding (Bassiouni, 1982). As such, international treaties have been a crucial source of international law which is commonly used by the International Criminal Court to prosecute cases of human rights abuse at an international scope.

The international custom as a source of international law and its ability to secure human rights paradigms internationally can be found through the diplomatic correspondence, press releases, executive decisions, governments comments on drafts that are created by the international law commission and the official manuals on the legal questions. More importantly, the activities of the international organs such as the United Nations General Assembly has led to the adoption of international custom which eventually contribute to the creation and expansion of the international law on human rights, trade and even environmental regulations. Populism is increasingly facilitating the use of customary law in human rights based cases that are conducted according to the international laws principles (Hostovsky Brandes, 2019). The ability of the international law in securing human rights and other key aspects of importance such as environment and trade is its ability to bind states even those that are yet to consent to the rules. Whereas international treaties are only bound to those that have consented to them the customary law does not require any consent which makes it an effective tool for advancing human rights principles.

Opposition of Customary Law Application in International Law

At the same time, there has been significant contest against the use of customary law in international law in international criminal law. This is because the rules which are derived from the customary law are imprecise and at times vague in nature. The application of customary law in international law can therefore be contested against due to the principle of legality which require high specificity and legal certainty. At the same time, the customary law application as a source of international law can be supported by the argument that the principle of legality only requires the prosecution and punishment to be based on clear provisions of international law when a crime was committed (Petersen, 2017). One support of the application of the customary law in the international law is the International Criminal Tribunal for the former Yugoslavia which requires rules of international humanitarian law to be beyond doubt and to be part of the customary law. Overall, the primary role of the customary law in international law is to fill the legal gaps which complicate the proceedings of the international law. As such, the customary law helps to interpret the International Criminal Court written rules (Petersen, 2017). At different times, the ICC has invoked the Article 21 (1) (b) and to some extent confirmed customary law especially in proceeds of cases which involves crimes against humanity.

Conclusion

It is evident that the customary law is widely accepted as a secondary source of international law and helps in the interpretation of the international law. At large, the two-element approach such as in the case of The Prosecutor v. Bosco Ntaganda shows the continued support and application of customary law in helping define and resolve the legal gaps in the interpretation of the international law during key criminal proceedings. The evidence of opinio juris is highly accepted in expounding how customary law can be used to understand some cases at the international level. The customary law despite the existence of ambiguity will continue to shape how international law is applied by the ICC in ruling fundamental cases especially those that challenge the existing customs and values of the different communities.

References

Bassiouni, M. C. (1982). The proscribing function of international criminal law in the processes of international protection of human rights. Yale J. World Pub. Ord., 9, 193.

Davidson L. (2019). The Importance of International Law. In: Essays Reflecting the Art of Political and Social Analysis. Critical Political Theory and Radical Practice. Palgrave Macmillan, Cham. https://doi.org/10.1007/978-3-319-98005-8_3

Diala, A. C. (2017). The concept of living customary law: a critique. The Journal of Legal Pluralism and Unofficial Law, 49(2), 143-165.

Fox, G. H., Boon, K. E., & Jenkins, I. (2017). The Contributions of United Nations Security Council Resolutions to the Law of Non-International Armed Conflict: New Evidence of Customary International Law. Am. UL Rev., 67, 649.

Hostovsky Brandes, T. (2019). International law in domestic courts in an era of populism. International Journal of Constitutional Law, 17(2), 576-596.

Klein, D. F. (1988). A Theory for the Application of the Customary International Law of Human Rights by Domestic Courts. Yale J. Int’l L., 13, 332.

Petersen, N. (2017). The International Court of Justice and the judicial politics of identifying customary international law. European Journal of International Law, 28(2), 357-385.

Pocar, F. (2020). Returning to Customary Law. In The International Criminal Court: Contemporary Challenges and Reform Proposals (pp. 298-302). Brill Nijhoff.
Konderla, J. (2018). International Customary Law in the Jurisprudence of the ICTY and the ICTR. Wroclaw Review of Law, Administration & Economics, 8(2), 287-300.

Svaček, O. (2017). Brothers and Sisters in Arms As Victims of War Crimes: Ntaganda Case Before the ICC. Czech Yearbook of Public and Private International Law, 8(1), 346-357.

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