Diane Foley, the mother of journalist James Wright Foley, is the president and founder of the James W. Foley Legacy Foundation. Art Sotloff and Shirley Sotloff, parents of journalist Steven Joel Sotloff, are the founders of the 2Lives Foundation.

Between 2012 and 2014, our children — James Foley and Steven Sotloff — were taken hostage, tortured and killed in Syria by members of the Islamic State. We were promised by two administrations that their murderers would be brought to justice. We watched as the Syrian Democratic Forces (SDF), a Kurdish-led coalition of local troops in northeastern Syria backed by U.S. forces, captured more than 10,000 ISIS prisoners.

Northeastern Syria, which borders Turkey, is a critical zone in which our U.S. troops, with our international coalition, have supported the Kurds in the fight against ISIS. The SDF have been guarding the 10,000 ISIS fighters and their 70,000 family members in camps. They have been awaiting extradition and trial.

Among them are Alexanda Kotey and El Shafee Elsheikh, two suspected members of the “Beatles,” the British ISIS fighters responsible for killing the hostages. We have waited, month after month, for the U.S. government to find ISIS leader Abu Bakr al-Baghdadi and other culpable ISIS fighters, and to finally prosecute Kotey and Elsheikh for the horrors inflicted on our children.

Earlier this week, we learned, with the rest of the world, that President Trump was abruptly pulling back U.S. forces in northeastern Syria and abandoning our local allies. Now we have heard the administration’s avowals that it has sent U.S. troops to take Kotey and Elsheikh into custody and to secure their captivity in Iraq.

This is, to be sure, welcome news. But it is not enough. While we are grateful to hear that these two particular ISIS fighters are now in custody, what of the other ISIS fighters and their families? What about the local civilian population and vulnerable Kurds who have helped contain ISIS as Turkey assaults this Syrian border territory? What will happen to the evidence of ISIS crimes in the region around Raqqa?

And now, on top of everything else, we learn of Turkish President Recep Tayyip Erdogan’s latest threat to send 3.6 million Syrian refugees into Europe. While he has vowed to place ISIS fighters under Turkish custody, his remarks have — probably intentionally — awakened uncertainty about the prisoners’ fates, given that he also promised to send them to their home countries — even though most of those countries have refused to accept them.

ISIS thrives in this chaos. Last month, al-Baghdadi issued a call to his followers to free the prisoners held in Syria. The Pentagon has stated openly that it does not have the troops to take charge of ISIS prisoners if the Kurds are unable to do so. With U.S. forces abandoning their posts and the SDF facing a Turkish invasion, who will ensure that the ISIS fighters and their families do not escape?

What message are we sending the world? Our U.S. troop withdrawal suggests that it is okay to abandon our allies, to no longer care about the suffering of innocents, and to kidnap and kill Americans abroad without any accountability. Do we fellow Americans not care about four young Americans — two journalists and two aid workers — who were taken hostage, tortured and brutally killed while working in Syria?

We implore President Trump to reconsider this decision and to deny the Islamic State the opportunity to regroup and continue its reign of terror. Yes, we must try Kotey and Elsheikh in our federal criminal courts; and if convicted of these brutal crimes against our citizens, they must be sentenced to lifetime imprisonment. Yet we must also capture al-Baghdadi, the ISIS leader, and provide leadership in seeking international justice for the radical Islamists’ horrific crimes against humanity, inflicted both on the innocent people of Syria and our children, American citizens left behind.

If we ever want to stop terrorists, they must face the consequences of their horrific crimes. All of them, not just a representative few.

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