Let's up the stakes to remove much of the bait.
1: fines for undocumented workers. Right now, the max is like $5K for the third offense. Not much incentive to make sure that they're legal. Raise it to $15K for the first offense, $30K for the second, and $50K for the third. Fines can be used to cover the cost of the wall, which will become superfluous, or can go to find the unemployment insurance.
2: Be prepared for a drastically revamped guest worker program as conservative businessmen start lobbying to make sure that they can get these workers from South of the border, including refugee status for South Americans fleei g their countries.
3: the draw of the criminal element to this country, in particular, drug smugglers and dealers. make all drugs legal for purchase by adults (21 and older) a couple countries have gone that far, focusing on rehab versus incarceration. The crime rate dropped along with drug usage. Pushers have been pushed out of business, quality of drugs improved, and overdoses reduced.
The floor is open.