Trump's 'endless rants' reveal which Democrat he fears most: MSNBC's Morning Joe and Mika

MSNBC's Joe Scarborough and Mika Brzezinski agreed President Donald Trump feared one Democratic candidate over any other.

As Democratic candidates drop out of the primary and coalesce around Joe Biden, the "Morning Joe" co-hosts said Trump's obsession with former vice president was betrayed by his constant public statements about him, in addition to the Ukraine scheme that got him impeached.

"He seems rattled," Brzezinski said. "Just looking at his tweets -- and he's going after [Mike] Bloomberg, he's going after Biden, he's going after the press. He's trying to bring up old videos concocting ways that these candidates look like they've said something terrible. I mean, there is an all-on onslaught to take on the emerging candidate."

Trump has been trying to stir up resentment among Bernie Sanders supporters against Biden, and Scarborough said the purpose was clear.

"It's fascinating how much Donald Trump fears, he's petrified politically of Joe Biden," Scarborough said. "He obviously is seeing internal polls that show that he must be doing badly in a lot of those swing states against Joe Biden because, again, Joe Biden was a man that Donald Trump feared so much that he allowed himself to be impeached over Joe Biden, trying to dig up dirt from a foreign leader in exchange for military funding."

"I mean, only the third president in U.S. history to be impeached," Scarborough added, "and he did it to try to stop Joe Biden, and now, of course, he goes to these rallies and he just rants endlessly about the Democrats trying to steal this process from Bernie Sanders. He's just, again, obviously really shaken and disturbed by the prospect of facing Joe Biden."