What we have instead is a regulation that almost prohibits immigration, but which has a whole bunch of grey areas, exceptions to the rule that qualify you for some special status, and courts that are overloaded by a factor of ~100 relative to what they would need to do their job, or overloaded by a factor of ~10 relative to what they would need to do a terrible pro forma job. While waiting for a court date (let's say you walk in and claim asylum) you are granted a special status by administrative custom which says that nobody is coming after you until after your status is adjudicated. Deportation is "deferred", and can be rescinded after the fact based on adjudication. Previous administrations have "prioritized violent crimes" for deportation, leaving about 20 million people at a time outside the system of legal permanent residency, and another 40 million of their family members who rely on them with legal status but precarious. Being custom rather than law, when Stephen Miller and his white supremacist posse comes in they can suspend that, and work at odds with the court and the process. They literally wait until these people check in with the courts and black bag them on their way out of the courtroom.

The US agricultural, construction, and food service sectors have come to almost completely rely on this system permitting either nominally illegal cash-under-the-table work, or "I can't actually prove he's illegal" work, or work performed under a green card sought after the delays and deferred prosecutions in that court date permit the immigrant to start a family and see their kids through college.