You want enforcement? Make it simple....you suspect a company of hiring illegals...report it to the local cops and the fine involved for illegal hiring (at least $5,000 for each illegal)....goes to you for reporting the company. Company has issues about fines....fine...we’ll make it a personal tax for hiring a non-US resident without a visa. You as the reporting authority get a $5k tax credit next year. The key here...is to avoid letting the border patrol do their job because they can’t, and the other government agencies can simply lock their front doors and go home. We won’t need them anymore...just regular folks reporting the illegals and the companies doing business.
That would work!