When a 19-year-old British teenager who ran away to join ISIS in Syria announced her desire to return home, it blew open the long-simmering question of what governments should do with returning jihadis and their families.

In a series of interviews, Shamima Begum, who married a Dutch ISIS fighter and recently gave birth, appealed for public sympathy, despite showing little remorse for ISIS atrocities.

In an interview with the BBC on Monday, she said the 2017 Manchester Arena bombing, in which 23 people died, was justified because of Western airstrikes in ISIS territory.

The public backlash was swift and by Tuesday, Britain announced its intention to strip Begum of her citizenship. Her family’s Mohammed Akunjee said they were considering “all legal avenues to challenge the decision.”

Begum’s case represents the legal and moral conundrum facing countries as ISIS nears its final defeat in southeastern Syria, with potentially hundreds of jihadists — many currently in jail or refugee camps — wanting to come home.

No legal obligation to assist ISIS followers

There is little political will in Europe to allow former ISIS fighters to return, as shown by the UK Home Office’s decision to revoke Begum’s citizenship.

At its height, ISIS controlled an area the size of Great Britain and ruled over 10 million people. It was estimated that the area included more than 40,000 international citizen from 80 countries, according to data from The International Centre for the Study of Radicalisation (ICSR).

Today, the territory is just a few hundred square meters as the US-backed Syrian Democratic Forces (SDF) push through ISIS’ last holdout in Syria. Now, thousands of ISIS members, including women and children, are in SDF custody — of whom hundreds are believed to be from European nations.

Few countries have embassies or extradition treaties with Syria. Nor have they shown any desire to go to the areas where ISIS fighters and families are being held, and put their government representatives in harm’s way, said Joana Cook, Senior Research Fellow at the ICSR at King’s College London.

Externally, though, pressure for action in mounting. On Sunday, US President Donald Trump threatened to release hundreds of foreign fighters captured in Syria unless European governments take them back and put them on trial.

The British government is under “no legal obligation to collect people” from SDF prisons, said Alex Carlile, a British barrister, cross-bench member of the House of Lords and former independent reviewer of terrorism legislation. if fighters wanted to return they would have to find assistance from places with consular representation, such as Turkey, he said.

“Like so many things President Trump says, it is accompanied by not a great deal of research,” Carlile told CNN.

Repatriation

Only a small number of nations, including Russia, Indonesia, Lebanon and Sudan, have allowed ISIS followers to return from Syria and Iraq.

“(European) countries are naturally reluctant to take back people who create a danger to their national security,” Carlile said. “The inevitable consequences of the attrition of ISIS (are) they revert to increased terrorism attacks in Europe.”

The UK has found a way to circumvent the issue, at least as far as dual nationals are concerned — revoking their citizenship. UK Home Secretary Sajid Javid told the House of Commons Monday that more than 100 people had been stripped of their British passports.

But the government is barred under both British and international law from rendering a citizen stateless. In the case of Shamima Begum, Javid seems to be getting around this by “reworking” British immigration legislation, said Hashi Mohamed, a former special adviser to David Anderson, the current independent reviewer of UK terrorism legislation.

Mohamed, now a barrister specializing in public law, said Javid seemed to be relying on a section in the 2014 Immigration Act, which states that nationality can be revoked if there are “reasonable grounds for believing that the person is able, under the law of a country or territory outside the United Kingdom, to become a national of such a country or territory.”

Mohamed said Javid’s move opened a can of worms and risked creating a “two-tiered British nationality.”

Javid said he plans to use “all powers available” to block British fighters and supporters of terrorism from returning to the UK, and is “considering” an update to the country’s 668-year-old treason legislation.

He added that 900 British people are believed to have traveled to fight in Iraq and Syria. Of those, 180 were killed and 360 have returned, leaving 360 still believed to be “somewhere in the region.”

France, meanwhile, is reportedly considering repatriating around 130 jihadi fighters of French origin — a proposal that has come in for stiff criticism from opposition groups.

Germany’s Foreign Ministry said in statement sent to CNN that it “is examining possible options to enable German nationals to leave Syria, especially in humanitarian cases.”

Prosecution

But “it is clearly not as easy as what has been put forward in the United States,” Reuters reported German Foreign Minister Heiko Maas as saying Monday, ahead of a Brussels meeting with EU counterparts. “These people could only then come to Germany if we can ensure they are immediately put in custody. It’s not clear to me how all that can be guaranteed.”

Prosecutions will face a number of hurdles, however, as it will be hard to obtain enough evidence against many of the ISIS supporters to secure convictions.

The issue was highlighted in Britain’s Parliament last year, when it was revealed that only one in 10 of all returned jihadists in the UK were prosecuted.

In many countries traveling to ISIS-held territory is not a crime in itself — although the UK has just passed a law making travel to a terrorist hotspot illegal — nor it is illegal to marry an ISIS fighter.

And while many countries have laws against aiding or abetting terrorist organizations, finding evidence for such crimes can be difficult.

“For all kinds of legal reasons, much of what is called ‘battlefield evidence’ in this case would not be admissible in court, either falling short on evidential grounds or because of the manner in which it was obtained. We do not, for example, use intercept evidence in UK courts,” Shiraz Maher, the director of ICSR, wrote in the New Statesman.

“I would guess there is a good deal of intelligence on these people, but converting (it) to evidence will be difficult,” Carlile said.

Wives of fighters

Experts have also noted that it could be difficult to prosecute non-combatant women like Begum.

While it is easier to gather evidence against male fighters, as ISIS propaganda and social media feeds have images of men perpetrating violence on the battlefield, “women were not featured in any propaganda at all,” the ICSR’s Cook told CNN. “Generally the kind of pictorial evidence which would be easier to prosecute a male is not that available for women.”

And then there are the children.

According to a 2018 report co-authored by Cook, at least 730 children have been born inside ISIS territory to foreign nationals, including 566 born to Western Europeans.

The report said EU officials have “stressed the need for EU member states to recognize these infants and adopt a case-by-case basis for their return and reintegration.”

“However, many European governments have yet to announce concrete policies,” it added.

De-radicalization

A 2017 European Commission report that looked into the issue of returning jihadists found a “second generation of returnees (who are) more battle-hardened and ideologically committed… and may have come back with violent motives: to harm EU citizens.”

The report advised a case-by-case assessment of each return, who will have a “cocktail of risk factors” like a low threshold for violence, post-traumatic stress disorder (PTSD), connections to international terrorist networks and further radicalization.

These concerns mean European countries will find themselves monitoring returnees who are not sent to jail.

In the British context, they could be added to the country’s terrorism watch list, which currently has around 20,000 people on it — only a fraction of whom are under detailed surveillance.

“If there is a decision not to prosecute, then the second stage would be a terrorism prevention and investigation measure (TPIM),” Carlile said.

Those restrictions, which can last up to two years, include electronic monitoring, phone and computer limits, relocation and limits on the people they meet.

Another route is a de-radicalization program, many of which are ill-equipped to deal with a new generation of female jihadis, Cook said.

In the UK, the Home Office’s Prevent program, which is the central plank of Britain’s strategy to combat terrorism, has been criticized for creating an atmosphere of distrust in the Muslim community.

There are no easy answers for the problem of returning jihadis in the face of countless atrocities perpetrated by ISIS, and the security threat returnees pose to Europeans.

But European countries are bound to find an answer, Cook said, as they are based on the rule of law. “That means they are obliged to help their citizens.” However politically unpalatable it may be.