When Stephen Colbert isn't busy being un-funny, he's busy screwing up basic facts.

On Tuesday, the CBS host addressed President Trump lawyer Rudy Giuliani taking offense to something said by National Review’s Jonah Goldberg, a longtime outspoken critic of the current president.

Goldberg said in an interview with Fox News’ Sandra Smith, “I am sure that Rudy Giuliani spends big chunks of his days chain-smoking cigarettes, white-knuckling it, just hoping another tweet doesn’t show up.”

Giuliani responded eventually, “There is a moron on Fox claiming I chain smoke cigarettes worrying about the President’s tweets. Don’t smoke cigarettes. Hate ‘em. Smoke only premium cigars and I hope this idiot is not a lawyer because if he is he should sue his Law School.”

If you think that's stupid, just keep reading.

Later that evening, Colbert figured the Goldberg-Giuliani spat would make for good late-night fodder.

“Even Trump’s allies are worried about how his lawyers are dealing with the tweet storm,” Colbert said. “Just ask conservative columnist and guy at a magic convention inviting you back to his hotel room, Jonah Goldberg.”

The last bit there is a reference to Goldberg's bearded appearance, which he laughed off. But as for the assertion that Goldberg is a Trump ally, Colbert is just plain wrong, and so wrong that one wonders whether he did any reading or research at all in putting together this not-terribly-funny joke.

Goldberg loudly and publicly opposed Trump throughout the 2016 GOP primaries. In fact, Goldberg once got into a public fight on social media with the then-presidential candidate.

As Mediaite’s Joseph A. Wulfsohn noted further, the National Review columnist has also “ blasted [Trump’s] performance at the Helsinki summit and placed blame at the president’s feet for the spending bill he signed into law earlier this year. He called Trump a ‘clown’ and said he tweets like a ‘14 year old girl’ back in 2015. Goldberg even referred to Trump as a “bane of humanity.’”

Yeah, yeah, Colbert is just a comedian. How can he be expected to know such things?

Colbert made his "Daily Show" debut in 1997. From there, he morphed slowed into a caricature of a right-wing political commentator. He kept at that gag for roughly seventeen years until 2014, when he made the jump to network television.

Though he dropped the faux Bill O’Reilly routine at CBS, he has kept up the political commentary (because who doesn’t love totally great and awesome Russia investigation jokes just before bed?). For a guy who comments nightly on American politics, you’d think he’d at least know who is and who isn’t an ally of President Trump.

Then again, maybe Colbert actually knows Goldberg is a harsh Trump critic, and he still believes the National Review commentator is an “ally” because he has praised the White House on at least a few issues.

If that’s enough to make a person a Trump "ally," well, then Colbert really is the perfect embodiment of the psycho with-us-or-against-us nature of today’s hyper-partisan politics.

It’s almost enough to make a guy miss David Letterman.

Almost.