The US government, of course. It always is.
It took the Kuwaitis to fire an alleged American Jihadi from a position he held in their country, as an airplane mechanic, in December 2014. It took the Turks to deny him entry into their country. And it took the Egyptians to deport him to the U.S.
Could these backward and benighted countries be looking out for their own better than the US does?
US Army veteran Tairod Nathan Webster Pugh was stopped—why, oh why? “keep jihadis OUT, not in”!—attempting to cross over into Syria, presumably not for the purpose of touring the ruins.
This avid Bin Laden supported was a former U.S. Air Force mechanic and had worked as a mechanic for American Airlines. And that was perfectly fine. So long as Pugh was endangering Americans stateside, he was safe from the American authorities (whose, constitutional duty it is to protect Americans).
Here in the US, labor and civil rights legislation guarantee that business can’t risk discrimination lawsuits should they fire bad people. They’d rather risk the lives of good people.