Immigration is an enumerated power of the federal government according to the US constitution. The Federal government has the obligation to establish a ‘uniform standard of naturalization’. Having patchwork enforcement, state by state is unconstitutional. Obama has an obligation to enforce the law through deportation of those who are caught and found here illegally. The states have the legal right to sue the US federal government over anyone who has been caught, sent to the federal government, and released, only to be caught again in the same state.
That is the best route to go at this point in time. Do what sheriff Joe is doing, arrest them, hold them until the feds show up to claim them. If the feds don’t show up, then continue to hold them. They don’t have legal access to the system the way that US citizens do, the rights that US citizens have do not apply to them.
The longer that Obama refuses to uphold the law, the longer the states can hold those detained.
We pretend that "immigration" Is among the enumerated powers of the federal government but initially it wasn't. Take a look at what the constitution said about "importing such persons' before 1828 ~
You probably imagine the United States was a very popular place for folks to emigrate to in the early 1800s ~ but it wasn't. You had to be rather desperate to want to come here. The sea voyage was very dangerous and most of our great cities had not yet been cleared of the malarial swamps that killed people by the thousands every year.
A climate disaster in Europe that occurred repeatedly throughout the 1800s made America very popular ~ when the choice was death by starvation or a voyage to Baltimore or Halifax.