People who don't click the link may assume a broader scope than what he said. While I believe he is going the wrong direction, it is a Constitutional puzzle what to do in the situation he is talking about. He's not talking about deporting adults for their parent's crime. He is talking about not letting undocumented grownups stay just because they have a dependent child that was born here, the so-called anchor babies. Families in that situation have generally been treated with leniency either because of principles or because it is such a bad look to go after them, but Trump's public position now is zero tolerance.
There is a Constitutional gap because the 14th Amendment was written in 1866 with the direct purpose of clarifying that all of the slaves born in the United States were citizens. There was no immigration process then. There were no visas. Anyone who could arrange the journey could move to the United States. It wasn't until 1924 that you need a visa and quotes were established. If Trump does what he is talking about here, it will certainly get to the Supreme Court. The ACLU will be itching to represent a deported legal citizen and the Supreme Court will have to rule. I'm not gonna bet on what they will decide, not simply because there are so many Trump appointees but because if they decided to be strict constructionist the 14th Amendment really wasn't written to address the children of people who came into the country illegally. I won't be shocked if they said that doesn't count.
I don't know if 47 will be different. There are signals that he is taking things more seriously. But people do forget how lazy 45 was. He did damage, but he promised a LOT more damage than he delivered because he is lazy and cares a lot more than he pretends to about what his detractors say about him. It is HIGHLY likely that he will report that he has deported 98% of undocumented immigrants, but the job is immensely more difficult than he presents it. We have estimates how many there are, but obviously they didn't get counted. Trumpism talks like the main issue is people sneaking across the border or showing up at the checkpoints and Biden letting them in, but the former are uncounted and more likely smugglers than immigrants and the latter are usually staying in contact and cooperating with legal processes. The bigger picture is people who get a temporary visa and then disappear and don't renew. Those people are very hard to find and we don't know how many there are because any of them may have not renewed because they left again. It is a reasonable supposition that the Trump administration will make some high profile showy moves and find that the bulk of the work is too difficult, which is one of the reasons his predecessors haven't done it, and then declare victory.