When President Biden took part in a Zoom call with lawmakers from the Congressional Progressive Caucus last weekend, an aide passed him a note that read, “Stay positive. You are sounding defensive.”

Sources familiar with the call said Biden “intentionally” read the note out loud for a moment of levity during a call with anxious lawmakers.

And on a separate call with centrist House lawmakers — which some sources described as “tense” — the president lashed out at Rep. Jason Crow (D-Colo.), Puck News reported Tuesday.

“First of all, I think you’re dead wrong on national security. You saw what happened recently in terms of the meeting we had with NATO. I put NATO together. Name me a foreign leader who thinks I’m not the most effective leader in the world on foreign policy,” Biden said, raising his voice.

“Tell me! Tell me who the hell that is! Tell me who put NATO back together!” 

As the discussion around Biden withdrawing from the race has picked up steam and grown heated in recent weeks, so has the president. Those on calls with Biden, since his dismal debate performance last month, have described him as defensive and angry. 

In recent days, he has also dug in, telling lawmakers, donors and voters that he’s not going anywhere. 

“We’re dealing with an old, angry man. It’s very Trumpian in some ways. But it’s not a good look,” said one Democratic strategist, who wants Biden to remain in the race. “His mood describes the moment we’re in right now and we need someone to lead us out of this mess.”

“But it’s apparent our candidate is not in a good place,” the strategist said. 

It’s an open secret among those who know Biden that he has “an Irish temper” and can veer from cool to hot rather quickly. In recent weeks, his frustration has spilled into interviews, speeches and calls with allies. 

The Biden campaign did not comment. 

But sources familiar with Biden’s calls with lawmakers say the president was not defensive but open to input and repeatedly solicited feedback from lawmakers. One source familiar with the matter said the exchange with Crow ended with Biden asking for more information. 

Asked to respond to the exchange with Biden on CBS’s “Face the Nation” on Sunday, Crow said, “Listen, you know, this is a tough business. There’s a lot at stake. Emotions can run high … I think the president heard our message very clearly, and in fact he promised to come back to us with more information.”

But in an interview with NBC’s Lester Holt, conducted two days after the attempted assassination on former President Trump, Biden also lashed out.

When Holt asked if he wanted to “get back on the horse” after the presidential debate, a combative Biden replied: “I’m on the horse. Where have you been? I’ve done 22 major events. Met thousands of people. Overwhelming crowds. A lot happening. I’m on the horse.” 

Throughout the interview, a seemingly frustrated Biden called out Holt and journalists for not spending time scrutinizing Trump’s lies at the debate or statements made by Trump’s vice presidential pick, Sen. JD Vance (R-Ohio), about his running mate in years past. 

“He’s said some things about me, but see what he said about Trump,” Biden told the news anchor. “What’s with you guys? C’mon man.”

And at a fiery rally in Detroit last week, Biden also railed against the news media.

“They’ve been hammering me because I sometimes confuse names,” he said. 

“I say ‘that’s Charlie’ instead of ‘Bill,’” Biden said. “But guess what? Donald Trump has gotten a free pass.”

Biden’s allies say he has to come at this party fracture from a position of strength — even if it sounds defensive at times — to convey that he’s the candidate and Democrats have to get behind him if they have any intention of beating Trump. 

“If anything, he has to remain defiant in this moment to make it clear that he’s the nominee and he is pushing forward to defeat Trump,” one Biden ally said. “Anything else would be seen as weak and it would lead to even more chaos.”

“You made me the nominee,” Biden said at the Detroit rally last week. “No one else. Not the press. Not the pundits. Not the insiders. Not donors.” 

For months, behind the scenes, Biden has expressed exasperation with his poll numbers, wondering why he’s in a dead heat with Trump in national surveys, sources say.

The Washington Post reported in December that Biden also “complained that his economic message had done little to move the ball,” even as jobs numbers were at historic highs and the economy was growing.

“There’s been a frustration that has been building, even before the debate,” said one Democratic donor. “What they don’t understand is that we’re angry. We feel like we’ve been deceived.” 

The anxiety has only built since the debate in recent weeks, as a growing number of lawmakers have asked Biden to step aside. On Wednesday, Rep. Adam Schiff (D-Calif.) became the latest lawmaker to call for Biden to withdraw from the race. 

“Our nation is at a crossroads,” Schiff said in a statement to the Los Angeles Times. “A second Trump presidency will undermine the very foundation of our democracy, and I have serious concerns about whether the President can defeat Donald Trump in November.”

Still, Schiff said the “choice to withdraw from the campaign is President Biden’s alone.” 

Biden allies say they don’t expect the president to buckle to any pressure. 

“There’s so much raw emotion going on right now. But the president thinks he can win,” one ally said. “And he means it. That’s why it’s frustrating to him when people doubt him.”