Fox News' Chris Wallace is once again calling out pro-Trump spin on the network, even slamming one contributor on air in a tense exchange.

Wallace spoke Monday about the explosive New York Times report that former National Security Adviser John Bolton in his upcoming book writes that President Trump told him he wanted to continue withholding aid to Ukraine until officials helped with investigations into former Vice President Joe Biden and his son.

To get a sense of how "big" this news is, one only has to look at Trump supporters "spinning like crazy that it isn't big news," said Wallace. This only reinforces that this is a "really important development in this case," he continued, per Mediaite.

Wallace went on to observe that it's now "much, much less likely" that Trump's impeachment trial will wrap up on Friday without any witnesses being called, as the Bolton news makes it "awfully hard" for Republican senators on the fence about calling witnesses to vote against doing so.

Fox News' Chris Wallace on the Bolton news: "If you want a sense of how big the news is that we've heard in the past 12-14 hours, listen to the Trump supporters...spinning like crazy that it isn't big news and you get a sense that this is really an important development." pic.twitter.com/o5xl6xj09e — Justin Baragona (@justinbaragona) January 27, 2020

Not long after, Wallace got into an argument with contributor Katie Pavlich about the idea of calling Bolton to testify after she claimed that in "every impeachment beforehand, the witnesses that were called had been called in the House before being brought to the Senate."

"In the Clinton impeachment, they'd been called by the independent counsel," Wallace told her, adding, "Get your facts straight!" Brendan Morrow