This a structural problem; even if the language of the Constitution confers protection on foreign citizens (which I believe it does, to some extent), there are only certain situations in which foreign citizens have standing in U.S. courts.
If they don't reside in the U.S. they basically have no venue to ask for relief. Even if the parent is right that it is a violation of international law, enforcement of international law is essentially voluntary.
If they don't reside in the U.S. they basically have no venue to ask for relief. Even if the parent is right that it is a violation of international law, enforcement of international law is essentially voluntary.