We don't need a border wall. nope. What we do Need, apparently escapes Trump. A national identity card. Tied to DNA. Fingerprints, the whole nine yards. if you can't prove your status then you ...shh...cant get a job. Or housing, or exist here legally. And then the feds can legally remove funding to states that ignore enforcing immigration laws. That would be the common sense way to approach this issue.
It'd have to be free or it will be ruled discriminatory.
Laws inherently discriminate, that's their purpose. Even on this board, you cant say certain words, because they are banned. I think it's fair to expect people that want to live here, be expected to accept legal immigration standards. And those that hire them, doubly so. The Constitution says no one is above the law. Not even immigration law. Sanctuary states violate the constitution, thence are unconstitutional , aren't they? Is there a constitutional lawyer in the room? Can states just ignore federal laws like this?