Comment by convolvatron

Legally. With due regard to the rights of those involved, and when detention is necessary, with humane treatment. In particular honoring due process, where people have the right to to at least be seen by a judge. The right to communicate with their families, and when deportation is necessary, send them to their country of origin instead of another continent entirely or paying some prison somewhere to detain them indefinitely. That when people are detained at all it on the orders of the a judge, expressed in a warrant. That while under detention they should have access to legal services, and have an avenue to complain about their treatment if necessary.

This was all very well understood and hashed out through law and precedent over many decades.