Some of the more restrained reactions to GOP presidential front-runner Donald Trump’s suggestion that Muslims need to be excluded from American immigration programs until Congress gets a handle on the issue of terror have come from his competitors in the race.

“Unhinged” came from Jeb Bush. “Offensive” was from Marco Rubio. And more.

But the most pointed attacks came from those who simply said it was unconstitutional.

William Banks of Syracuse law school told the Wall Street Journal, “Aside from being outrageous, it would be unconstitutional.” Laurence Tribe at Harvard’s law school agreed.

Talking to U.S. News & World Report, Harvard Law professor Gerald Neuman said the idea is “discriminatory in a fashion that’s totally inconsistent with constitutional principles.”

However, that doesn’t mean it’s unconstitutional, apparently.

Eric Posner, a professor at the University of Chicago Law School, pointed out that the Supreme Court “has held consistently, for more than a century, that constitutional protections that normally benefit Americans and people on American territory do not apply when Congress decides who to admit and who to exclude as immigrants or other entrants.”

In “Stop the Islamization of America: A Practical Guide to the Resistance,” renowned activist Pamela Geller provides the answer, offering proven, practical guidance on how freedom lovers can stop jihadist initiatives in local communities.

“This is called the plenary power doctrine,” he continued. “The court has repeatedly turned away challenges to immigration statutes and executive actions on grounds that they discriminate on the basis of race, national origin, and political belief, and that they deprive foreign nationals of due process protections.”

He said while the court hasn’t ruled specifically on religious discrimination, “it has also never given the slightest indication that religion would be exempt from this general rule.”

Eugene Volokh, a First Amendment specialist at the UCLA School of Law, mostly agreed.

“As a policy matter, I think that banning entry by Muslims would be a very bad idea, for many reasons. But, like many very bad ideas, it might not be unconstitutional,” he wrote.

In fact, the Legal Information Institute at Cornell cites this provision of federal law:

Whenever the president finds that the entry of any aliens or of any class of aliens into the United States would be detrimental to the interests of the United States, he may by proclamation, and for such period as he shall deem necessary, suspend the entry of all aliens or any class of aliens as immigrants or nonimmigrants, or impose on the entry of aliens any restrictions he may deem to be appropriate.”

NPR described the reaction to Trump’s comments – which came in the aftermath of an attack by two Muslims in California, including a woman who arrived from Pakistan, when they shot and killed 14 at a county Christmas event and injured another 21 – as a “torrent of criticism.”

Specifics of Trump’s plan haven’t been confirmed, but Trump said U.S. military members who are Muslim would be allowed into the U.S.

And the authority might be even stronger if a President Trump could persuade a Congress to go along.

Akhil Reed Amar, who is at Yale Law School, told NPR the Supreme Court “has never completely repudiated a very long-standing doctrine – known as the ‘plenary power’ doctrine – that gives Congress very broad power to keep aliens of all sorts from entering American if Congress so chooses.”

Volokh noted Posner’s opinion, and said, “I would add that, in Kleindienst v. Mandel (1972), the Supreme Court applied the ‘plenary power doctrine’ to the exclusion of people based on their political beliefs, despite the Free Speech Clause. The cases that Posner is referring to, together with Kleindienst, suggest that the exclusion of people based on their religious beliefs is likewise constitutional.”

He noted that, “at this point, the precedents counsel in favor of the constitutionality of such a rule.”

Posner pointed out there even is a precedent for Trump’s idea.

“In 1891, Congress passed a statute that made inadmissible people who practice polygamy (directed, at the time, at Mormons), and in 1907 extended this ban to people who ‘who admit their belief in the practice of polygamy.’ While Congress later repealed the latter provision (the former seems to be still on the books), no court – as far I know – ruled it unconstitutional.”

He said it’s clear, “The plenary power doctrine is universally loathed by scholars and some have argued that it is effectively a dead letter. But any honest answer to a journalist’s question about whether Trump’s plan to ban Muslim immigration is unconstitutional should start with the plenary powers doctrine, and observe that it would be an uphill battle to persuade the Supreme Court to abandon a century of precedent.”

He said it’s unfortunate that scholars – “who certainly know better” – are telling journalists who don’t like Trump’s ideas what they want to hear.

“Not everything that is stupid or offensive is unconstitutional,” he said.

And when the Iranian hostage crisis developed under President Jimmy Carter, a Democrat, Front Page Mag reports he issued orders designed to pressure Iran. One of them said Iranians were banned from entering the U.S. unless they opposed the Shiite Islamist regime – or had a medical emergency.

He said, in 1980, “The Secretary of Treasury and the Attorney General will invalidate all visas issued to Iranian citizens for future entry into the United States, effective today. We will not reissue visas, nor will we issue new visas, except for compelling and proven humanitarian reasons or where the national interest of our own country requires.”

Carter also ordered 50,000 Iranian students in the U.S. at the time to report to immigration offices and face deportation if they were in violation of their visas.

Talk radio giant Rush Limbaugh noted Carter’s work.

“Over here, everybody in the establishment in the political class, Republican, Democrat, media, you name it, is all claiming that what Trump said is dumb, stupid, reckless, dangerous, unconstitutional, while it is the law of the land. And it was utilized by Jimmy Carter, no less, in 1979 to keep Iranians out of the United States, but he actually did more. He made all Iranian students already here check in, and then he deported a ton of ’em,” he said.

“There is precedent for everything Donald Trump has said he wants to do. And if you listen to the wizards of smart in this country and our political establishment, you will think that this stuff is just unheard of, it’s almost unspeakable, it’s just indecent. Here we have in the establishment the reputed best and brightest, the smartest. We’re not even qualified to be in their company no less. And they’re dunces on this.”

In “Stop the Islamization of America: A Practical Guide to the Resistance,” renowned activist Pamela Geller provides the answer, offering proven, practical guidance on how freedom lovers can stop jihadist initiatives in local communities.

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