"I don't really have the answers, either. :)
But I do know that having two sets of laws, or (!) having one and some hybrid international law that applies here is simply impractical."
The problem here is that you are confusing my answers of suing and other rights. Early in this discussion I answered someone post about MD illegal's filing a lawsuit about our ID restrictions.
Convict this guy the same as you would any other drunk driver, but he should not have the right to sue us if he is done wrong by the system. A redo may be in order, but take suing off the table.
In addition he should not be set free until that time; nor should any other illegal because we won't find them again until they break another law.