Much more interesting though: Donald Trump may be able to be super aggressive on deportations. Not only for Khalil and the Tren de Aragua members, for everyone.

As far as I can tell, the prevailing case law is Wong Wing v. United States (1896) and Harisiades v. Shaughnessy (1952). In Wong Wing, the Supreme Court said that deportations are civil cases that require no due process unless there is a crime being charged. Which means that the USA can use "summary measures" with no court at all for deportations where there is no crime, but the alien is of a class or character judged deportable under a law, such as a supporter of terrorism, or the "foreign policy risk" clause citable by the Secretary of State under existing law. Such matters are judged solely by the executive branch as the Supreme Court summarized in Turner v. Williams by saying "No limits can be put by the courts [i.e. no judicial review at all] upon the power of Congress to protect, by summary methods [summary methods means rapid deportation without a hearing], the country from the advent of aliens whose race or habits render them undesirable as citizens, or to expel such if they have already found their way into our land, and unlawfully remain therein."

That means that all immigration courts are essentially optional process measures offered by the executive branch, rather than arms of the judicial branch, and indeed when you go and look, all of these courts are administered directly by the Dept of Justice, not the court system. It looks like the executive branch can pull back about as much of that as they would like - I haven't seen legislation that establishes the framework for any of those and I think it's entirely Executive branch jurisdiction. I.e. it's kind of become a "norm" to have those courts, but a President is free to change that norm. However, as soon as a crime is charged, then you're in the jurisdiction of the courts, as due process kicks in before you can be found guilty of a crime (and subsequently deported due to said criminal activity being proven in a court of law).

But if the DoJ, SoS, or executive branch want to eject you under a law that allows it for non-criminal behavior, then there is no judicial review required and no first amendment protection. That's what the Court adjudicated in Harisiades v. Shaughnessy where they allowed the deportation of Communists despite First Amendment arguments that they should be allowed to express their views without deportation.

I think there's an awakening coming to just how much power of removal the executive branch has, granted under current law and by a deference established by long-standing Supreme Court rulings. The current Justices may overrule some of this given that it's 70-120 year old case law, but today rapid removal without possibility of judicial review is permitted for many, many, individuals and groups, as specified in current laws by Congress and administered on its behalf by the Executive branch.