As of this morning there are about 12,000 alien children in U.S. custody. 10,000 came by themselves. 2,000 came with a maybe mom or maybe dad. The wailing about "breaking up families" is shrill and mistaken.
The U.S. government told the maybe moms and maybe dads to cross at legal entry points and claim asylum. They did not.
These policies were made law by the George W. Bush administration and enforced by the Obama administration.