In his major policy speech on foreign policy delivered yesterday in the battleground state of Ohio, Republican presidential candidate Donald Trump finally made it clear who exactly should be barred from the United States: himself.

The candidate plainly stated that “those who do not believe in our constitution, or who support bigotry and hatred, will not be admitted for immigration into the country”. Since Trump, who is known to have expressed bigoted and hateful opinions about Mexicans and Muslims, and who has repeatedly demonstrated a tenuous grasp of the constitution, already resides in the United States, I assume he will opt for Mitt Romney-style self-deportation.

Obviously, I’m being sarcastic. But not that sarcastic, to be honest with you.

We have become accustomed now to hearing a new version of Trump’s Muslim ban almost every time the candidate opens his mouth on the issue, but we should remember that his proposal was born out of politics and not principle. In December 2015, rival candidate Ted Cruz was stealing Trump’s thunder by saying the US was now “at war” because of the San Bernardino attacks. Trump had to one-up his competition, so he proposed a “total and complete shutdown of Muslims entering this country”, and everyone forgot about Cruz for the moment.

Then, after the public debated the constitutionality of a religion-based ban, Trump later announced that he would instead “suspend immigration from areas of the world when there is a proven history of terrorism against the United States, Europe, or our allies”. Are we to assume that Trump isn’t opposed to terrorism per se but only terrorism against the US and its friends?

And by July, he stated that he would bar entry to those coming from “territories and terror states and terror nations”, whatever that means. In the intervening months, as the website thinkprogress.org has pointed out, he has exempted from the ban his own friends who are Muslim, Muslim Americans in the military, Muslim world leaders and Muslim athletes. Trump’s Muslim ban has been remixed almost as often as Change the Beat by Fab 5 Freddy.

The latest version of this failed immigration policy has Trump tilting back to the days of the cold war. Proposing an “ideological screening test”, Trump now says that his program of “extreme vetting” will screen out those who “do not share our values and respect our people”. Going further than his past proposals, Trump now demands we bar those “who have hostile attitudes towards our country or its principles – or who believe that Sharia law should supplant American law”.

It’s hard to take any of this seriously. Trump is proposing that the freedoms of immigrants, and especially Muslims, entering this country be curtailed to the point that they cannot hold “hostile attitudes”. But who is to decide when an attitude is hostile enough to warrant exclusion? Do we really expect the authorities to patrol not only our borders but also our thoughts? Does Donald Trump, of all people, not realize that you might say contradictory things about any given topic just to get ahead?

Trump’s precedent for this absurdity is the old McCarran-Walter Act of 1952, which sought to ban communist thought from the country, but which ended up keeping such notable people as Nobel-prize winning novelist Gabriel Garcia Marquez, French actor Yves Montand and Canadian politician Pierre Elliot Trudeau from crossing our borders.

“It made us look to the rest of the world like a people other than the people we are” is how the late US senator Daniel Patrick Moynihan characterized the policy. “It misrepresented America. It said we’re afraid of ideas, can’t handle them, don’t like people speaking their minds. That’s not who we are at all.”

Trump’s unworkable policy proposal will further alienate Muslims around the world because it tells them they are guilty until they can prove to him they are innocent. It also insults all immigrants by policing their thoughts and beliefs and every citizen by suggesting we can’t think for ourselves. For a man who says he bravely stands up to “political correctness”, Donald Trump seems awfully ready to enshrine it into law.