It was considered whack-job territory, not worthy of serious discussion, the latest ride on the Crazytown Express.

And now, suddenly, the mainstream media are being forced to grapple with the possibility that it might be true.

Could COVID-19 have been created in — and escaped from — the Wuhan lab?

For well over a year, most media types dismissed that theory — and some ridiculed those who talked it up. The debate became wrapped up in politics, like just about everything else related to the virus — because President Trump was a leading proponent of the thesis.

Asked by a reporter in May 2020 whether he’d seen anything to give him confidence in the lab scenario, Trump said, "Yes I have. Yes I have. And I think the World Health Organization should be ashamed of themselves" for buying China’s spin.

That gave the press an easy out: Trump was trying to blame the virus that was then starting to savage America on his new scapegoat in Beijing.

"Nobody Is Buying Trump’s Wuhan Lab Theory," the Guardian declared.

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The liberal site Vox claimed back in March 2020 to have "debunked" the lab "rumor." But this week, Vox belatedly ran an editor’s note saying that "scientific consensus has shifted."

And so it has. Which is why the network morning shows all mentioned it Tuesday, although only "CBS This Morning" had a full report.

The headline on Tuesday’s Washington Post fact-checker column: "How the Wuhan Lab-Leak Theory Suddenly Became Credible."

To be clear, this theory, like all the others, remains unproven. We are talking about circumstantial evidence here. But the environment changed over the weekend when the Wall Street Journal, citing U.S. intelligence sources, reported that three Wuhan researchers were hospitalized with Covid-like symptoms in November 2019 — shortly before the first virus case was reported.

Back in February, Tom Cotton said there should be an investigation because the Chinese have a history of dishonesty.

"Tom Cotton Keeps Repeating a Coronavirus Conspiracy Theory That Was Already Debunked," the Washington Post said.

"Senator Tom Cotton Repeats Fringe Theory of Coronavirus Origins," the New York Times said. (Good thing no one at the paper asked him to write an op-ed on the subject.)

Now there have been exceptions to these sweeping dismissals. New York magazine, in January, ran a lengthy piece exploring the lab hypothesis.

Former Times science reporter Nicholas Wade, in a Medium essay early this month, gave the theory credence. He blames the lack of journalistic curiosity, in part, on "the migration of much of the media toward the left of the political spectrum. Because President Trump said the virus had escaped from a Wuhan lab, editors gave the idea little credence."

Wade also writes: "Science reporters, unlike political reporters, have little innate skepticism of their sources’ motives; most see their role largely as purveying the wisdom of scientists to the unwashed masses. So when their sources won’t help, these journalists are at a loss."

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Now everyone should recognize that it’s extremely difficult to investigate such things when Beijing retains such tight control of Chinese society. But the criticism here is not that the media failed to crack the case; it’s that they didn’t even try.

I’ll give the last word to Post columnist Josh Rogin, who tweeted:

"If you are writing a piece defending yourself for being wrong for a year about the lab leak hypothesis by blaming everyone else except yourself for your own wrongness, you haven't learned a thing and you are just engaged in bull** navel-gazing that literally nobody cares about."