If an immigrant who the government claims is a gang member can be deported to El Salvador without any due process rights, then why not a U.S. citizen? That was the nightmarish scenario immigration advocates and constitutional law experts were considering on Monday after President Donald Trump aga in pushed a provocative plan to deport U.S. citizens who have been convicted of unspecified crimes. Trump discussed the issue in the White House with El Salvadoran President Nayib Bukele, who has agreed to deposit people deported from the U.S. into a notorious prison. “We always have to obey the laws, but we also have homegrown criminals that push people into subways, that hit elderly ladies on the back of the head with a baseball bat when they’re not looking, that are absolute monsters,” Trump told reporters. “I’d like to include them.” Follow live politics coverage here Last week, White House press secretary Karoline Leavitt said Trump was interested in deporting “heinous, violent criminals” who are U.S. citizens to El Salvador “if there’s a legal pathway to do that.” It is unclear if the administration is referring only to naturalized citizens. In rare circumstances, naturalized citizens can have their citizenship revoked if, for example, they obtained it through fraudulent means. During Monday’s White House meeting, Trump said that Attorney General Pam Bondi is “studying the law.” The White House and Justice Department did not respond to messages seeking additional information about the proposal. “It is pretty obviously illegal and unconstitutional,” said Ilya Somin, a professor at George Mason University’s Antonin Scalia Law School. Immigration law that gives the government the authority to deport people simply does not apply to U.S. citizens, noted Emma Winger, a lawyer at the American Immigration Council, a nonprofit advocacy group. Anthony Kreis, a professor at Georgia State University College of Law, noted that the British policy of removing certain alleged criminals from colonies to be put on trial elsewhere was one of the grievances during the lead-up to the American Revolution. “I can’t see how exiling someone is permissible as part of the bundle of rights that are fundamental to citizenship — doubly so if the effort to house American citizens overseas means turning a person over to a foreign authority,” he added. David Bier, an immigration expert at the libertarian Cato Institute, said Trump’s remarks show how “absolutely critical it is for the courts to put an immediate stop to this extrajudicial imprisonment by foreign proxy.” “U.S. citizens may not be deported to imprisonment abroad. There is no authority for that in any U.S. law,” he added.  The U.S. government alleges the people sent to El Salvador are violent gang members, although some have been sent without the ability of courts to determine whether they have been correctly identified, raising serious constitutional issues. In one case arising from Trump’s effort to invoke a war-time law called the Alien Enemies Act, the Supreme Court has already ruled that people subject to such deportations have due process rights. In a separate opinion in that case, Justice Sonia Sotomayor addressed the extreme nature of some of the government’s arguments. “The implication of the government’s position is that not only noncitizens but also United States citizens could be taken off the streets, forced onto planes, and confined to foreign prisons with no opportunity for redress if judicial review is denied unlawfully before removal,” she wrote. The parallel legal dispute over Kilmar Abrego Garcia, the immigrant who the Justice Department has admitted was mistakenly deported to El Salvador, also has bearing on any proposal to deport U.S. citizens. Abrego Garcia was not charged or convicted of any crimes in the United States or El Salvador and was whisked off to El Salvador before courts could intervene to ensure that he could vindicate his due process rights. The government alleges he is a member of the MS-13 gang. Although a judge has ordered that Abrego Garcia be returned, the Trump administration is now saying that he is outside their jurisdiction and that the decision on whether he is returned is solely up to El Salvador. Bukele said on Monday he would not do so. The Supreme Court also weighed in on the case, saying that although the government was obliged to “facilitate” Abrego Garcia’s return, the courts could not infringe upon the president’s authority to conduct foreign policy. If that logic is applied to U.S. citizens, they could potentially be summarily deported without being able to challenge it. Although Trump has said he would only want to target criminals, there is also no reason the government could treat others who have not been convicted of crimes in the same way. “The U.S. government has already deported someone to this prison illegally and claimed no recourse to get them back, so the courts must shut down this unconstitutional train wreck before U.S. citizens are unlawfully caught up in it,” Bier said. In the United States, prisoners still have basic constitutional rights and often challenge their convictions and conditions of confinement. It is unclear if they have any such rights if detained in an overseas prison. Last week, Homeland Security Secretary Kristi Noem said at an event in Phoenix that Bukele had told her that people sent to the prison in El Salvador “will never leave.” Trump’s plan is “an additional reason why courts must force Trump to return Abrego Garcia and others illegally deported to imprisonment in El Salvador,” Somin, the law professor, said.  Megan Lebowitz, Didi Martinez and Katherine Doyle contributed. This article first appeared on NBCNews.com. Read more from NBC News here: Columbia student detained while attending naturalization ceremony, lawyer says Florida GOP tries to crack down after Ron DeSantis’ state staff helped raise political cash Inside an anti-vaccine autism summit in the age of RFK Jr. ...read more read less