Joe Biden threw down the gauntlet on Monday, challenging any Democrats who want him to step aside to come forward and run against him.

In a letter to Hill Democrats returning from their July 4th recess, Joe Biden gave his most forceful signal yet that he will not yield to pressure to give up his shaky re-election bid.

Urging the party to unite, Biden warned that the continued handwringing over his viability was only helping one person: Donald Trump.

“The question of how to move forward has been well-aired for over a week now. And it’s time for it to end. We have one job. And that is to beat Donald Trump," Biden said.

Biden throws down gauntlet

Biden echoed his defiant message in an interview with MSNBC's Morning Joe in which he lambasted the party's "elites." He challenged any Democrat with doubts about his candidacy to "run against me."

"I’m getting so frustrated by the elites. Now, I’m not talking about you guys, but by the elites in the party. They know so much more. But if any of these guys don’t think I should run, run against me. Go ahead. Announce — announce for president. Challenge me at the convention.”

Democrats have been panicked over Biden's ability to win re-election ever since his debate debacle on CNN.

Only a day before Biden sent his letter to Hill Democrats, a group of senior House Democrats including Jerry Nadler (D-Ny.) said they wanted him to step down during a private group call.

Dems falling in line

Within a day of Biden's big push, there were signs that Biden was starting to quash dissent in the party.

New York Democrat Jerry Nadler backtracked Tuesday on his previous suggestion for Biden to step aside.

“Whether or not I have concerns is besides the point. He is going to be our nominee and we all have to support him,” Nadler said.

While Biden, unsurprisingly, thinks he is the only candidate who can beat Trump, others feel that Biden is actually doing Trump a favor.

But Democrats frustrated with Biden's hold on the party acknowledged to Axios that dissent seems to be losing momentum following Biden's show of force.

"When there's this kind of show of force, it's hard to imagine people are going to speak up against him," one House Democrat told Axios.