The Future of International Criminal Law is Domestic

On 16 June 2025, the Higher Regional Court of Frankfurt sentenced a Syrian doctor to life imprisonment for torturing and killing detainees in military hospitals run by the Assad regime. The verdict marks not only a milestone for the families of the victims and survivors of a regime that took over 200,000 lives and forced more than six million people to flee, but also serves as a powerful affirmation of international criminal law. As international institutions face mounting pressure and political obstruction, domestic courts are becoming central to the enforcement of accountability. Far from being mere substitutes, they increasingly function as the structural backbone of international criminal justice – upholding its norms, compensating for its institutional weaknesses, and keeping its promise alive. This case underscores the transformative potential of universal jurisdiction: not as an abstract legal principle, but as a functioning mechanism for justice.

What is the International Criminal Court’s role in holding members of the former Assad regime accountable?

The trial and conviction of Alaa M. (judgment of 16.06.2025, Case No. 5 – 3 StE 2/21-4 – 2/21) is a reminder that domestic proceedings often fill an accountability gap inherent in the structure of the International Criminal Court (ICC) and its relationship to the jurisdictions of its state parties. From its inception, the ICC was designed as a court of “last resort”, intervening only when states are unwilling or unable to prosecute international crimes themselves. This so-called principle of complementarity, enshrined in Art. 17 (1)(a) of the Rome Statute of the ICC, limits the Court’s jurisdiction strictly to situations in which domestic efforts to ensure accountability have failed.

Yet, in the face of systematic atrocities and the near-total collapse of the rule of law in their home country, many understandably turn to international institutions, hoping for impartial investigation and credible prosecutions. In Syria’s case, the scale and brutality of the conflict have led to repeated calls to the ICC for a (re-)opening of the Syria Situation and investigation as well as prosecution of those responsible. Many argue that justice for Syrians requires an international response.

However, the ICC’s intervention hinges on questions around jurisdiction, i.e. whether the Court is authorized to put members of the former Syrian government and military to trial for war crimes and crimes against humanity allegations. According to the Rome Statute, the Prosecutor may initiate investigations by him or herself (proprio motu investigations, Arts. 13 (c), 15), provided that the state on whose territory alleged crimes are perpetrated is a party to the Statute. Syria, however, has not ratified the Rome Statute or otherwise accepted the Court’s jurisdiction. Another way for the Court to exercise its jurisdiction would be a referral by the UN Security Council (Art. 13 (b)), acting under Chapter VII of the United Nations Charter which enables it to take coercive action with respect to threats to the peace, breaches of the peace and acts of aggression. That door was closed in 2014, when Russia and China, permanent members of the Security Council, used their veto to block a referral – and there is no indication that this political impasse is likely to change.

Since neither condition is met, and a Security Council referral remains off the table, the ICC currently lacks a viable path to investigate or prosecute crimes committed in Syria. As a result, former members of the Assad regime remain beyond the reach of international justice – for now.

Universal jurisdiction as a driving force of international criminal law

However, it would be a mistake to assume that this geopolitical deadlock rules out all forms of justice for its victims and the Syrian people. As the conviction of Alaa M. by the German Higher Regional Court shows, accountability for atrocity crimes does not depend solely on international institutions. In recent years, several ICC state parties have launched proceedings based on the principle of universal jurisdiction – prosecuting individuals for crimes committed abroad – regardless of where the crime occurred or the nationality of the perpetrator or victim.

Under universal jurisdiction, states may investigate and prosecute the most serious international crimes even in the absence of any territorial or personal link to the case (see Principle 1 (1) of the Princeton Principles on Universal Jurisdiction). The only requirement is that the accused is present on the prosecuting state’s territory. These domestic proceedings hold enormous potential for addressing severe human rights violations and must not be underestimated.

Germany is widely regarded as a pioneer in this field. The principle of universal jurisdiction is codified in Art. 1 of its Code of Crimes Against International Law (CCAIL – Völkerstrafgesetzbuch), and the German Federal Prosecutor General has opened numerous investigations into extraterritorial crimes. Beyond cases concerning Afghanistan, Eritrea, The Gambia, Yemen, the DRC, Libya, Mali, Nigeria, Pakistan, and Chechnya, it is above all, those relating to Syria and Iraq that stand out in terms of scope and impact.

These investigations often begin as so-called structural investigation proceedings (Strukturermittlungsverfahren): a preliminary stage that focuses on mapping out the organizational context of alleged crimes and identifying broader patterns of criminality before individual suspects are targeted.

This approach has proven particularly effective in the Syrian context, where structural investigations focus on alleged crimes committed by the Islamic State as well as those attributed to former members of the Assad regime. The most prominent example remains the 2022 conviction of former intelligence officer Anwar R. for crimes against humanity – the first criminal trial worldwide concerning the torturous practices of the former Syrian regime.

The conviction of Alaa M.: another cause for hope

The judgment delivered by the Higher Regional Court on 16 June marks another milestone for international criminal law. Alaa M. was found guilty of war crimes, including the killing and cruel or inhumane treatment of protected persons (Section 8 (1) Nos. 1 and 4, (6) No. 2 CCAIL), as well as crimes against humanity (killings, torture, and sexual violence, Section 7 (1) Nos. 1, 5 and 6 CCAIL), and murder (Section 211 of the German Penal Code). The court concluded that he committed these crimes in Syria between 2011 and 2012 as part of a group of doctors in Homs known as the “elimination group”, who targeted civilians perceived as opponents of then-president Bashar al-Assad.

The investigations by the German Federal Prosecutor were made possible by the close ties Alaa M. had built in Germany. Born and trained in Homs, he worked in a military hospital in Damascus before arriving in Germany in 2015. There, he resumed his medical career as an orthopedic and trauma surgeon, settling in Hesse with his wife and two children. It was only after two Syrian refugees recognized him from their time in detention and reported him to the authorities that proceedings were initiated. The trial lasted almost three and a half years, during which more than fifty witnesses were heard. Their testimonies proved crucial to the outcome, despite many of them having lived under threat from the Assad regime until its collapse in 2024, making their participation all the more courageous.

Centering successful outcomes of domestic jurisprudence

Among the many hardships the ICC currently faces, its inability to adjudicate atrocity crimes in urgent and large-scale contexts is particularly disheartening. In light of the immense suffering at stake, it is all the more crucial that member states continue to pursue justice in their own national courts, mirroring the Rome Statute framework and invoking the principle of universal jurisdiction.

Such domestic proceedings should not be viewed as the second-best option. While it is true that national trials may lack the ICC’s institutional resources and have so far mostly targeted lower-ranking perpetrators of the Assad regime, they offer distinct advantages. In terms of both efficiency and effectiveness, domestic courts can act more swiftly and in greater proximity to affected communities. The trial of Alaa M. exemplifies this: it was initiated by survivors who recognized him, provided testimony, and thereby made the conviction possible. While the proceedings were admittedly lengthy in his case – it took 188 trial days for the court to reach a verdict, of which 155 were devoted to witness examination – they still required considerably less time than international trials, which span up to six years.

Importantly, domestic courts acting under universal jurisdiction can step in precisely when international mechanisms fail – effectively reversing the complementarity principle. They not only serve justice in the absence of international avenues but may also lay the groundwork for future international trials. In that, national trials should be considered a central pillar of international criminal accountability, rather than a less desirable substitute.

The growing number of domestic cases applying international criminal law is therefore to be welcomed, even if – or precisely because – it eventually results in fewer trials before the ICC in the future. This may ultimately reflect the success, not the failure, of the international criminal justice system. As former Prosecutor Moreno-Ocampo once noted, the absence of trials before the ICC is the best sign that international criminal law is working.

In the case of Syria, it is vital to highlight the promise of national proceedings. They reveal the positive ripple effects of an international legal order that, despite its limitations, empowers states to act. National trials addressing atrocity crimes should therefore be recognized and consistently upheld: as a source of justice, and as a sign of hope in the ongoing struggle to maintain the rule of law internationally.