During Wednesday's debate, Donald Trump repeated a claim that he's made again and again this campaign: that he opposed the Iraq war before it started. But Trump is wrong. In 2002, Trump came out in favor of the Iraq War. And there's ironclad, hard proof.

BuzzFeed's Andrew Kaczynski and Nathan McDermott found evidence when they looked through old recordings of Trump on The Howard Stern Show back in February. They came up with one hell of a scoop from the September 11, 2002, episode:

STERN: Are you for invading Iraq? TRUMP: Yeah, I guess so. I wish the first time it was done correctly.

"Yeah, I guess so" — the words of a true statesman, weighing in on the most important foreign policy question of the 21st century.

Here's the actual audio, in case you had any doubt (Iraq conversation starts at 3:40):

For a normal candidate, this would be a devastating blow to his credibility. This one of the key claims of Trump's candidacy. It's central to his theory that his unique, Trumpian judgment and intelligence makes him qualified to be commander in chief despite no foreign policy experience and even less knowledge.

We actually knew well before Kaczynski and McDermott's scoop that Trump was lying about his public opposition to the Iraq War; fact checker after fact checker looked into it and found zero evidence that he was ever against the war. As the Atlantic's James Fallows put it, in a piece written four days before the BuzzFeed audio discovery: "Trump. Is. Lying. About. Having. Publicly. Opposed. The. Iraq. War."

Yet Trump has continued to deny, even insisting during the debate (bizarrely) that the Howard Stern thing didn't count as endorsing the war.

Trump lied on Wednesday night, and has been lying throughout the campaign, about both his issues and his own past record. But the problem is that he can just get away with it. By virtue of being the Republican nominee, news outlets are forced to give Trump airtime, and it is very hard to disprove a dedicated serial liar on air if he just commits to their falsehoods. Dylan Matthews summed up this dynamic well:

Producers know that when you put someone who's likely to spew falsehoods and who's impervious to all attempts to correct them on the air, that person is going to get a lot of opportunities to repeat his falsehoods, and it'll be very hard if not impossible to debunk him. Viewers will get a healthy sampling of lies, and undoing that damage in the space allowed will be nigh impossible.

Matthews was writing last November, but so far nothing has changed. The moderators at Sunday's debate did not press him on his claim.

So despite the fact that we have concrete proof that Trump is lying about opposing the Iraq War, Trump's still claiming the very opposite at a nationally televised debate watched by millions.