Manchin had been considered among the likeliest Democrats in the Senate to break with his party and vote against Trump’s removal from office, especially after the senator floated the idea of a censure of the president instead. But ultimately, Manchin has said, he found the evidence that Trump abused his office and obstructed Congress’ investigation “overwhelming.”

The West Virginia lawmaker, who votes with Trump more often than any other Democrat in the Senate, on Monday fired off what appeared to be a warning at the president.

“Here’s the thing. I'm his best chance of having anything in a bipartisan way,” the senator said.

In an interview on MSNBC later Monday, Manchin swatted back more forcefully at Trump's "Munchkin" moniker and Trump’s assertion that the senator “couldn’t understand the Transcripts” of events at the center of the impeachment inquiry.

“First of all, the munchkin, I'm taller than him, I think, a little bit bigger than he is,” he quipped. “Not heavier — he's much heavier than me, but I’m a little taller than him so I guess he got that little bit off.”

Manchin added that he didn’t know Trump’s intent when the president referenced the transcripts.

“I hope he wasn't referring to because I’m from West Virginia, that we can’t understand or comprehend,” he said. “I think we do a pretty good job of that, and I understood it very well. I read it and I understood it.”

But he also said that while he expected Trump's broadsides, he would not stoop to the level of name-calling that Trump had.

“Do you think names bother me? Do I look like I’m small and fragile?” he asked. “Names don’t bother me. The president knows he can’t get to me that way. I'm not going to retaliate.”

He continued: “The people want a mature adult — that's what the president should be. That's who we want as our president. I want him to succeed. This is not personal with me. I mean, he can call me all the names he wants to. It makes him look like an immature adult. I hope he rises above that. I think it's best for our country.”

Manchin also bemoaned conservatives’ fury toward those who crossed Trump throughout the impeachment inquiry, including two impeachment witnesses who were removed from their administration posts and Sen. Mitt Romney, the only Republican to vote for the president's removal. Romney in particular has faced significant backlash from Trump and others in the GOP over his vote.

“It's hard to believe we've stooped this low,” Manchin said of the Romney fallout.

“We're separated enough,” he told MSNBC. “We have a divider in chief. What we need is a uniter in chief and I hope the president comes back to that.”

Still, he expressed confidence that the country would bounce back from this period of partisan animosity.

“I believe in our country, I believe in my state of West Virginia as Mitt believes in Utah. Good people. And good people finally come — basically they can only pull the wool over their eyes so long,” he said. “I hope the president changes his ways, I hope he becomes a responsible adult and I hope he succeeds. I'm going to work with him if we can, but I'm going to be an honest broker.”

