I recently spoke with constitutional scholar, Ilya Somin, about how courts often allow the government to infringe immigrants’ basic rights (such as free speech, freedom of religion, and equal protection) in a way they would never allow against US citizens. Professor Somin warns that these abuses often end up affecting US citizens. He also explains how the legal theory allowing these double standards, "the plenary power doctrine," was invented nearly a century after the ratification of the constitution by the same Supreme Court justices who invented the doctrine of "separate but equal" allowing segregation against blacks.
Professor Somin’s forthcoming book: https://www.amazon.com/Free-Move-Migration-Political-Freedom/dp/0190054581/ref=sr_1_1?keywords=ilya+somin&qid=1582529358&sr=8-1
Professor Somin's faculty profile: https://www.law.gmu.edu/faculty/directory/fulltime/somin_ilya