Some economic migrants are using children as chits, but the problem is fixable — if Congress acts.The latest furor over Trump immigration policy involves the separation of children from parents at the border.

As usual, the outrage obscures more than it illuminates, so it’s worth walking through what’s happening here.

For the longest time, illegal immigration was driven by single males from Mexico. Over the last decade, the flow has shifted to women, children, and family units from Central America. This poses challenges we haven’t confronted before and has made what once were relatively minor wrinkles in the law loom very large.

The Trump administration isn’t changing the rules that pertain to separating an adult from the child. Those remain the same. Separation happens only if officials find that the adult is falsely claiming to be the child’s parent, or is a threat to the child, or is put into criminal proceedings.

It’s the last that is operative here. The past practice had been to give a free pass to an adult who is part of a family unit. The new Trump policy is to prosecute all adults. The idea is to send a signal that we are serious about our laws and to create a deterrent against re-entry. (Illegal entry is a misdemeanor, illegal re-entry a felony.)

When a migrant is prosecuted for illegal entry, he or she is taken into custody by the U.S. Marshals. In no circumstance anywhere in the U.S. do the marshals care for the children of people they take into custody. The child is taken into the custody of HHS, who cares for them at temporary shelters.

The criminal proceedings are exceptionally short, assuming there is no aggravating factor such as a prior illegal entity or another crime. The migrants generally plead guilty, and they are then sentenced to time served, typically all in the same day, although practices vary along the border. After this, they are returned to the custody of ICE.

If the adult then wants to go home, in keeping with the expedited order of removal that is issued as a matter of course, it’s relatively simple. The adult should be reunited quickly with his or her child, and the family returned home as a unit. In this scenario, there’s only a very brief separation.

Where it becomes much more of an issue is if the adult files an asylum claim. In that scenario, the adults are almost certainly going to be detained longer than the government is allowed to hold their children.