Stephen Colbert said he was “shaken” to the core by President Donald Trump’s controversial meeting with Russian President Vladimir Putin on Monday, an event Colbert says should be classified as “treason.”

“Today has shaken me to my core, and I don't think I need to point out that, at 54, there's not a lot of core left,” Colbert said in his opening monologue on “The Late Show.” "OK, egotism plus naivete times false equivalence equals ... yeah, treason.”

Colbert dedicated a two-part “Double Stuf Oreo” version of his opening monologue to Trump and Putin after the two leaders met for a summit in Helsinki on Monday, just days after the U.S. indicted 12 Russian military intelligence agents for allegedly hacking DNC servers ahead of the 2016 election.

President Donald Trump and Russian President Vladimir Putin arrive for a meeting in Helsinki, July 16, 2018.(Brendan Smialowski/AFP/Getty Images) President Donald Trump and Russian President Vladimir Putin arrive for a meeting in Helsinki, July 16, 2018.

“I'm thinking that maybe the most patriotic thing we can do right now, is not point out the alarming behavior of our president, which could be divisive. But instead, just take it until he's gone,” Colbert joked. “Does anybody feel like taking it? ... OK, me neither. I was worried there for just a second.”

Colbert went on to highlight reactions from lawmakers on both sides of the aisle who opposed the summit, including former CIA Director John Brennan, who claimed Trump was "wholly in the pocket of Putin."

“Wow! Those are the worst reviews I've seen since Titanic. And I don't mean the movie,” Colbert said after reading a few of the reactions.

Trump said Putin vehemently denied charges of collusion during their meeting and brushed off the idea Russia had compromising information on him, but Colbert said he found that hard to believe.

“You don't see any reason? Do you own a mirror?” Colbert joked. "Because after throwing your intelligence community under the bus, you threw it in reverse and turned them into road burger."