Jake Tapper brought a moment of clarity to CNN when he called out Democrats for readily trusting indicted Rudy Giuliani associate Lev Parnas.

The CNN host took a shot at Democrats and their rush to accept the claims about the Ukraine controversy from Parnas, who has a “serious credibility problem,” during a segment on “The Lead” on Thursday.

(Video: CNN)

Parnas, who was indicted on charges of campaign finance crimes last year, has been claiming that President Donald Trump was directly involved in withholding aid to Ukraine in exchange for an investigation into former Vice President Joe Biden and his son Hunter.

“President Trump knew exactly what was going on,” Parnas told MSNBC’s Rachel Maddow this week, and posited that Attorney General William Barr “had to have known everything” about the Ukraine plan. Democrats rushed to sound the alarm over the claims, which the businessman continued to make on his media tour in the days leading up to Trump’s impeachment trial.

But Tapper pressed the pause button on the rush to accept Parnas’ anti-Trump narrative at face value.

“We can’t ignore Parnas has a serious credibility problem,” he told the CNN panel on Thursday.

“He’s under indictment for campaign finance charges. The foreign minister of Ukraine told CNN’s Christiane Amanpour that he doesn’t trust a word Parnas is saying,” Tapper said. “And yet, I see people out there on social media — Democrats — acting as if this guy is the second coming of Theodore Roosevelt or something.”

“It’s true,” CNN senior political reporter Nia Malika-Henderson agreed.

“And all of those reasons are why maybe people should want him to testify under oath,” she added. “Kellyanne Conway, for instance, says when he’s talking in a television studio he isn’t under oath, but there actually is a way to get him under oath if anyone is interested in vetting his claims.”

Malika-Henderson also noted it’s “unclear” if Republicans are even interested in hearing his testimony.

“It’s not clear if he has documents or if he’s essentially parroting a lot of the information that came out from the impeachment hearing from all of those hours of testimony, that essentially said the same thing,” she said. “How Parnas would know what’s in Trump’s head? Unclear. How Parnas would know what’s in Vice President Pence’s head? Also unclear. It might be worth having him before Congress to talk about it.”

“It does square with a lot of things that we know that have been ascertained,” Tapper remarked, pointing to the transcript of Trump’s phone call with Ukrainian President Volodymyr Zelensky in which he mentioned Giuliani.

“So it’s not as though the broad contours of what he’s saying are out of nowhere,” Tapper added. “It’s just the specific references to ‘Pence knew, Barr knew, Trump knew.’ How would he know?”

While Parnas has claimed he was “basically on the team” digging up dirt in Ukraine, the president has denied knowing him except for having met at various fundraisers over the years. Others have also slammed Parnas’ claims and attorney Victoria Toensing asserted that he “absolutely lied” in his allegations.

Victoria Toensing flat-out calls Lev Parnas a liar after explosive allegation implicating Barr in Ukraine corruption https://t.co/RGC2VQml6n — Conservative News (@BIZPACReview) January 16, 2020

Politico reporter Laura Barrón-López noted on Thursday’s CNN panel how it all validates “one of the biggest arguments from Republicans” on the allegations against the president, which is that, despite all the so-called evidence, there has been “no direct witness that has spoken to Trump.”