The already bitter fight between the White House and the progressive base over trade policy has turned ugly after President Obama said his critics on the left “don’t know what they’re talking about” and compared their arguments to conspiracy theories about “death panels.”

Progressives trade critics are up in arms over the comments, made Thursday night to a gathering of Organizing for Action, the grassroots group that spun off of Obama’s presidential campaign, at the Ritz Carlton hotel in Washington, D.C.

The president has been locked in perhaps his fiercest battle yet with the left flank of his own party over a massive new trade with a dozen Pacific-rim countries known as the Trans-Pacific Partnership. To get TPP approved, Obama needs Congress to grant him “fast-track” authority, which would give Congress only an up-down vote on final treaty. It’s practically impossible to achieve Congressional approval of treaties otherwise.

Close video President Obama dings MSNBC’s TPP coverage Ed Schultz delivers a passionate commentary on the dangers the TPP poses to American workers, a reaction to President Obama’s most recent comments on the trade deal. Sen. Bernie Sanders joins the conversation. Ed Schultz delivers a passionate commentary on the dangers the TPP poses to American workers, a reaction to President Obama’s most recent comments on the trade deal. Sen. Bernie Sanders joins the conversation. share tweet email Embed

“When people say that this trade deal is bad for working families, they don’t know what they’re talking about,” Obama said Thursday. “So I take that personally. My entire presidency has been about helping working families.”

“Some of these folks are friends of mine. I love them to death. But in the same way that when I was arguing for health care reform I asked people to look at the facts – somebody comes up with a slogan like ‘death panel,’ doesn’t mean it’s true. Look at the facts. The same thing is true on this. Look at the facts. Don’t just throw a bunch of stuff out there and see if it sticks,” the president added.

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And on Friday, Obama made a surprise appearance on a conference call with reporters and Labor Secretary Tom Perez. Obama took what seemed to be a shot at liberal lawmakers like Sen. Elizabeth Warren and progressive groups for “send[ing] e-mails out to their fundraising base that they’re working to stop a secret deal.” There’s “nothing secret” about the treaty, he said.

“It was like a lashing out … It’s what you call in tennis an unforced error,” Scott Paul, the president of American Alliance of Manufacturing told msnbc

Charles Chamberlain, the executive director of the Howard Dean-founded Democracy for America, criticized Obama’s remarks. “It’s shameful to see President Obama compare Democrats who oppose fast tracking the TPP through Congress to Sarah Palin and the delusional ‘death panels’ rhetoric. Frankly, it’s beneath this president to resort to such name-calling,” Chamberlain said.

Becky Bond, Political Director at CREDO Action, also said the comments were “beneath” the presidency. “It’s ironic that he claims critics of the TPP ‘don’t know what they’re talking about’ when it’s his administration that is refusing to release the text of his secret trade agreement to the public or even to members of Congress,” she said.

Progressives viewed the the criticism as a sign of desperation from the administration, which has struggled to wrangle support from Democratic members of Congress.

“The president is frustrated,” said Roger Hickey of the Campaign for America’s Future. “He’s losing the argument and he’s crosswise with his supporters and it’s unfortunate that he’s basically calling people names.”

“It’s not smart politics to insult the people who have been your supporters, and especially with something like death panels. Most of the people who are fighting Obama’s trade policy are the people who were fighting back against the right-wingers who called his health plan ‘death panels,’” Hickey added.

The White House has countered that TPP is the most progressive trade deal in history and includes strict labor and environmental protections that make this trade deal very different from previous ones.

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“The president has rightly built up significant credibility with progressives all across the country. And he feels confident in making the case to them and to the rest of the American people that the kind of agreement that he seeks is clearly in the best interest of American businesses, American workers and American middle class families,” White House spokesman Josh Earnest told reporters Friday when asked about the criticism.

He cited recent polling showing 97% of liberal Democrats support Obama.

“The president isn’t doing this because he enjoys the support of the Chamber of Commerce, he’s doing this because he has earned the support of middle class families across the country. And he’s earned that support by using the power of the presidency to go and fight for them,” Earnest added.

The dispute over trade has reignited tensions between the left and the White House, which have improved in recent years after reaching a nadir in 2011 when Obama pushed for a “grand bargain” on deficit reduction.

“Belittling progressives who represent the overwhelming majority of Americans in opposition to a trade deal written by corporations in secret is a return to the worst days of this White House,” said Progressive Change Campaign Committee co-founder Adam Green. “They are back to caving to corporate interests, forfeiting opportunities for greatness, and, in this case, costing millions of peoples their jobs and economic well being if successful.”

The most frustrating thing, as some liberals see it, is that the White House is spending huge political capital to pass a trade deal the base does not support, while not doing enough in their mind to support liberal priorities.

Ohio Democratic Sen. Sherrod Brown called president’s priorities “maddening.” “I think if you could get my colleagues to be honest, on the Democratic side, with you – and I think you can mostly – they will say they’ve been talked to, approached, lobbied and maybe cajoled by more cabinet members on this issue than any issue since Barack Obama’s been president,” Brown told reporters Thursday. “That’s just sad.”

RELATED: Senator Warren cites ‘rigged’ process in concerns on trade deal

Dan Cantor, national director of the progressive group Working Families, said Obama is “wrong” on trade. “If Democrats ever wonder why some people think both parties are in the pocket of Wall Street, secretive trade deals like this are one are a big reason why,” he said.

And David Segal, who runs the Internet freedom group Demand Progress, which also opposed TPP, turned Obama’s comments on their head. ”It’s clearly Obama who doesn’t know what he’s talking about when it comes to trade – just look at his disastrous Korea Free Trade Agreement, which he claimed would create 200,000-plus new American jobs but in just a few years has already cost us 60,000 and increased our trade deficit by billions,” Segal said.

Paul, of the American Alliance of Manufacturing, said the Barack Obama of the 2008 presidential campaign would not have supported the Barack Obama of 2015’s trade agenda. “It shouldn’t be a surprise to him, then, that a large portion of the base is upset and disappointed with his devolution on this,” Paul said.

MoveOn.org’s Anna Galland added that Obama’s trade agenda is “disappointing.” “MoveOn members have a ton of respect for President Obama – and we’re allies on a whole host of issues like achieving a diplomatic agreement with Iran. But he’s wrong on this,” Galland said.

Larry Cohen, the president of the Communications Worker of America, echoed the sentiment to msnbc. “The coalition against this version of Fast Track includes every union, nearly all environmental groups, faith, immigrant, consumer and community organizations. Our organization has fought by the President’s side for health care reform, the rights of immigrants, and nearly everything else. We remain by the side of all of our allies, on those other issues, but also in opposing Ryan-Hatch-Wyden Fast Track and we will continue to mobilize millions of Americans across political lines to defeat it,” he said.

The administration will need support from more Democratic lawmakers to secure approval of “fast-track” authority, along with a large chunk of Democrats aligned with the leadership of both houses of Congress.