Donald Trump picked up a bizarre theory from the front cover of the National Enquirer last year. It speculated that the father of Sen. Ted Cruz (R-Tex.) had been palling around with Lee Harvey Oswald in New Orleans before the Kennedy assassination, distributing anti-Castro literature. There was no evidence that this was true, except that Rafael Cruz was generally the right age and was of Cuban heritage and may have been in New Orleans at some point in that general time period — three factors that applied to thousands of other people, too. Trump’s assertion was quickly and widely excoriated.

What wasn’t considered odd, though, was that there would be conspiracies about the assassination of President John F. Kennedy. Americans broadly believe that Kennedy’s killing was a function of a broad-based conspiracy and not, as the government’s investigation would have us believe, a result of Oswald’s shots fired from the Texas School Book Depository. With new assassination documents being declassified by the government Thursday (after Trump declined to keep them confidential), it’s worth highlighting the rarity of the Kennedy assassination conspiracy in American thought: generally accepted, and — more remarkably in this moment — on a bipartisan basis.

The Washington Post and our polling partners at ABC News polled Americans on the assassination in 2013, on the 50th anniversary of Kennedy’s death. Overall, 6 in 10 Americans believed that the president was assassinated as part of a plot involving multiple people. That same percentage held steady among Democrats, Republicans and independents.

Imagine! Democrats and Republicans agreeing on something controversial that is tangentially related to politics!

Fairleigh Dickinson University conducts an annual poll to evaluate Americans’ opinions on other controversial or speculative issues. The most recent iteration, released in April, didn’t find other examples of bipartisan agreement in support of the theory.

There was broadly bipartisan agreement on the debunked, false and pernicious rumor that vaccinations have some link to autism (which, again, they do not). Only about 5 percent of Americans believe there’s a link (which they shouldn’t, because there isn’t). Republicans and independents were slightly more likely to say it was possibly true.

On a series of theories related to the political moment, though, broad disagreement.

Democrats broadly believe that Trump’s refusing to release his tax returns because he is hiding business ties to Russia. Republicans don’t. (His lawyers have reviewed his filings and say he isn’t.)

Most Republicans believe it’s certainly or possibly true that President Barack Obama is hiding details of his personal background (read: wasn’t born in the United States). (He was.) Most Democrats don’t.

Most Republicans also believe it’s certainly or possibly true that supporters of Obama committed rampant voter fraud in 2012. (They didn’t.) Most Democrats don’t (perhaps in part since they would have been out there committing the fraud).

Part of the divergence on those last three poll questions is a function of their subjects: current political actors and controversies. (Few people in 2017 spend much time debating the relative value of Kennedy’s policy decisions.) Part of it, too, is rooted in the stark political divide in the country right now, a divide that inclines people to believe the worst about their political opponents. (Like that a prominent Democrat engaged in paganistic rituals or that Trump had an impostor stand in for his wife.)

Part of the acceptance of the Kennedy theory, though, is rooted in an idea central to the political moment. Believing that there was a plot to kill Kennedy means believing that the institution of the federal government conspired to lie to the public — a belief that has been embraced widely in parallel with a growing distrust of American institutions. In other words, the political conspiracies in Fairleigh Dickinson’s polls are ones that ask us to question each other; the Kennedy assassination theory asks us to question the authorities.

Most Americans, regardless of party, are willing to.

Few, though, are willing to extend their partisanship to involve their political opponents directly in the assassination itself. That is largely reserved for the president.