“Are you guys enjoying March Madness?” Stephen Colbert asked his audience Monday night. “Speaking of madness: Donald Trump.”

“We’re on the brink of another crisis, because it really feels like Trump is gearing up to fire special counsel and guy wondering how much he’ll get for his book deal, Robert Mueller,” the Late Show host added, referring to comments Trump lawyer John Dowd made over the weekend about wanting to end the Russia investigation.

As for Trump’s tweet about the 13 “hardened Democrats” working for Mueller, Colbert added, “By the way, Mr. President, every time Mueller announces indictments, many Democrats are hardened.”

Over the weekend, Sen. Lindsey Graham said Trump firing Mueller would be the “beginning of the end” of Trump’s presidency. “Wait, it’s not even the beginning of the end of his presidency?” Colbert asked. “I thought we were at least at the middle of the beginning of the end! I should’ve gone to the bathroom when Reince Priebus left. Now, I’ve got to hold it to the midterms.”

Moving on to the Trump administration’s decision to fire Deputy FBI Director Andrew McCabe 26 hours before his retirement, Colbert said they were doing it all “wrong.”

“If you want to get rid of a cop two days before his retirement, you don’t fire him, you send him out on one last job with a rookie,” Colbert said. “And, because he was fired two days before his retirement, McCabe loses his $60,000 a year pension. $60,000, that's like half a porn star payment.”

“Now, this could all be perfectly innocent,” Colbert said, mouthing “it’s not.” He explained that “to avoid looking like he was trying to shut down the Russia investigation, all Trump had to do was not dance on McCabe’s grave.” But he couldn’t even do that, tweeting, “Sanctimonious James Comey was his boss and made McCabe look like a choirboy.”

“And Mr. Trump knows a lot about choir boys,” Colbert said. “Because everyone who works for him is going to sing.”

“Let that sink in for a second,” he continued. “This is a sitting president gloating about firing a respected, career FBI official, and smearing another whose firing led to the appointment of the special counsel. And none of that shocks me as much as the fact that he spelled ‘sanctimonious’ correctly.”