Is Trump’s Proposed Ban on Muslim Entry Unconstitutional?

Donald Trump’s plan for a “total and complete shutdown” of Muslims entering the U.S. was swiftly condemned by many Republican and Democratic presidential candidates.

But legal experts aren’t of one mind about whether the incendiary plan floated by the GOP candidate would survive judicial review.

Mr. Trump said Monday that, if elected, he would bar all Muslims from entering the country with very limited exceptions, such as allowing Muslims serving in the U.S. military to return home. He said he would lift the restriction when more is known about the security threat posed by Islamic terrorism.

Some constitutional scholars say there’s no debate.

“Aside from being outrageous, it would be unconstitutional,” said William Banks, a constitutional law scholar at the Syracuse College of Law, pointing to guarantees of due process under law.

“I believe Trump’s unprecedented proposal would violate our Constitution,” said Harvard Law Professor Laurence Tribe, according to NBC News. He said it would also conflict with the First Amendment’s religion clauses.

Other scholars who spoke to Law Blog were more hesitant to pronounce the Muslim immigration ban unconstitutional, at least as it applied to non-U.S. citizens. (Denying entry to American citizens, they said, would definitely not hold up in court.)

Constitutional challenges to immigration restrictions “face unusually tough hurdles,” Stephen H. Legomsky, of Washington University School of Law, who was chief counsel at the U.S. Citizenship and Immigration Services agency under President Barack Obama from 2011 to 2013. Most recently the professor served briefly as senior counselor to the Secretary of Homeland Security on immigration issues.

The hurdle he referred to is in the form of the so-called plenary power doctrine, a legal concept articulated by the Supreme Court giving Congress tremendous power over immigration laws. It was first laid down by the Supreme Court in the late 1880s when justices upheld the Chinese Exclusion Act, a federal law that suspended immigration of Chinese laborers. Repealed during World War II, it was the first major immigration restriction enacted into law and the first exclusion based on ethnicity.

The plenary power doctrine “states that the courts should show exceptional deference to Congress when it legislates in the field of immigration,” Mr. Legomsky told Law Blog. “Whether modern courts would uphold a racial or religious immigration restriction is difficult to predict.” The high court has reaffirmed the doctrine in a 1972 ruling denying entry to a self-described “revolutionary Marxist” from Belgium who sought a temporary visa.

UCLA law professor Eugene Volokh told Law Blog that Mr. Trump’s plan “may be a very bad idea, but under the plenary power doctrine it may very well be constitutional.”

Mr. Legomsky noted that courts have recognized exceptions to the doctrine. Deportation proceedings, for instance, may not be stripped of due-process protections.

It doesn’t appear that Mr. Trump would have to get congressional approval before advancing the Muslim ban, said Temple University law professor Peter Spiro. Congress has already given the president broad powers to suspend the entry of “any class of aliens as immigrants” if their entry would “be detrimental” to the nation’s interests.

Congress, Mr. Spiro said, could still block the plan by changing the law and stripping away that exclusion power delegated to the president.

Mr. Volokh said it’s also possible that the Trump plan could violate treaty agreements with American allies.

Clarification:  Mr. Trump’s proposed Muslim immigration ban would ​not likely ​require congressional approval​.​  A previous version of this post ​concluded that​ Mr. Trump’s plan would require authorization from Congress.