We need to STOP THE FLOW NOW!!!, and then worry about how to fix the situation with those aliens already here illegally. To spend time and law enforcement money on questioning people as to their legal status is not going to fix anything. Even if they deport them by the bus load, they'll be right back. Would you keep a ship in service with a huge hole in the hull, and just keep hiring more sailors with buckets to try to keep the thing from sinking, or would you put the ship in drydock first, fix the hole, and then dry out the bilges?
Charles