At one point during the back-and-forth debate on the topic of Federal Bureau of Investigation director James Comey, Cooper tells Lord, "You can't defend what the president of the United States just said".
On Friday night, Cooper's exhaustion, or maybe his frustration, boiled over during his conversation with commentator Jeffrey Lord.
Cooper interrupted him: "If he took a dump on his desk, you would defend it".
Defending Trump, Lord said that it was the president's prerogative to describe people as he saw fit.
"I don't care what he says to the Russian prime - to the Russians", Lord replied.
"If he took a dump on his desk, you would defend it", Cooper said, interrupting Lord. "I mean, he's the president of the United States. It was unprofessional. I am genuinely sorry", he wrote on Twitter. "I like having your voice on here, and I think you're an important voice to have", according to CNN's Brian Stelter.
Even still, Cooper has joined the annals of cable news history: He is still one of CNN's biggest ever shit-stirrers.
After a second of hesitation, the panel laughed awkwardly before Cooper continued.