Countries the world over remain inexplicably paralyzed in developing a co-ordinated response about what to do with ISIS fighters and their supporters. Under the watchful eyes of Kurdish forces, many are being held in detention camps in Northern Syria. Indeed many countries are refusing to repatriate their citizens.

The diplomatic spat between London and Ottawa this past week is a case in point. The United Kingdom revoked the citizenship of dual British-Canadian citizen Jack Letts — dubbed "Jihadi Jack" by British media — who is accused of travelling to Syria at age 18 to fight for ISIS. Revoking his British citizenship essentially makes him Canada's problem.

The onus is now on Canada to do something, which, during an election year, puts all of this under an intensely partisan microscope.

ISIS does not seem to be going away. Although subdued in Iraq and Syria, it is regrouping in other countries and regions of the world. (Reuters)

The truth of the matter is that while the coalition assembled to defeat ISIS territorially has more or less succeeded in achieving that objective, it is apparent that they gave little to no thought about what to do with ISIS members once they were captured or gave up the fight. But by working together, Canada and the United Kingdom can ameliorate the situation by supporting a multilateral response.

Sweden is already on task, trying to bring together an international coalition of countries that will support the creation of an international tribunal to prosecute ISIS fighters and others who supported the group. As an important first step, Sweden convened a high level meeting in early June, with officials from Germany, France, the United Kingdom and the Netherlands, as well as representatives from the European Union and the UN.

In an interview with the Financial Times, Sweden's Interior Minister Mikael Damberg made the case for a co-ordinated response, arguing "This is a moral and symbolic issue — will the world and Europe just treat this [ISIS] as another thing that happened? Or shall we have it written in the history books that we considered these as very serious crimes?"

Establishing an international tribunal is an idea with growing support. The foreign minister of the Netherlands has publicly called for the international community to establish such a tribunal, noting ISIS committed genocide and should face justice. As both the United Kingdom and Canada are signatories of the Genocide Convention, they have a responsibility to punish those who committed these atrocities.

International tribunals have been used in the past, most recently regarding the Rwandan genocide and war crimes committed during the conflict that destabilized the Balkans in the 1990s. Given that ISIS is a non-state actor that took over two large swaths of territory in two different countries, assisted by approximately 40,000 "foreign fighters" drawn from over 100 countries, it presents a unique case and one worthy of consideration.

Some human rights groups have criticized Sweden's proposal for a tribunal narrowly focused on ISIS, stating that a tribunal should also look into the crimes committed by the Assad regime in Syria also. That is fair criticism, but it does nothing to advance justice for Yazidis and other victims of ISIS in Iraq and elsewhere. Another criticism is that such a tribunal will be an expensive undertaking. No doubt this is true. However, it will amount to be a fraction of the costs of the combined military campaign to defeat the group.

A lingering threat

ISIS does not seem to be going away. Although subdued in Iraq and Syria, it is regrouping in other countries and regions of the world. U.S. Secretary of State Mike Pompeo admitted as much recently, saying, "There's certainly places where ISIS is more powerful today than they were three or four years ago. But the caliphate is gone and their capacity to conduct external attacks has been made much more difficult."

That's why now is the time for international response. This weekend's G7 summit meeting in France is the perfect opportunity to rally the groups' members around the common purpose of providing political and financial support to establish an international tribunal.

ISIS remains a threat to international peace and security and bringing its members to justice not only helps the group's myriad victims and ends impunity, it will also serve to discredit the group's ideology and expose it for being an enterprise of death and destruction. Canada and the United Kingdom should seize this opportunity to provide global leadership in upholding justice and human rights.

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