President Obama is increasingly frustrated with opposition at home to the Trans-Pacific Partnership. (Pablo Martinez Monsivais/Associated Press)

Pitching his Pacific free-trade initiative to business leaders last December, President Obama framed it as a foreign policy gambit: He mentioned the looming threat of China 18 times in remarks to the Business Roundtable.

Last week, while making the case to 200 liberal activists, Obama mentioned China only once.

Instead, in a 4,000-word address to Organizing for Action (OFA), Obama sought to place his trade pact alongside his signature domestic initiatives, including his health-care law, the auto industry bailout, student-loan consolidation and Wall Street reform.

The sharp shift in the way Obama is now presenting the Trans-Pacific Partnership (TPP), a 12-nation trade deal in the Asia-Pacific region, illustrates his biggest challenge as he tries to wrap up a late-term policy victory over fierce opposition from fellow Democrats.

His critics on the left are calling the TPP a job-killing, big-
business boondoggle aimed at satisfying K Street corporate interests. And that has put Obama under pressure to explain how the pact will help ordinary American workers and families. In his weekly radio address, he called the deal “vital to middle-class economics.”

It hasn’t been easy. Facing heat from Sen. Elizabeth Warren (D-Mass.), the AFL-CIO and even usually friendly MSNBC hosts, Obama has sounded incredulous that his progressive bona fides are coming under question.

“When people say that this trade deal is bad for working families, they don’t know what they’re talking about,” Obama told OFA, the advocacy group that evolved from his campaign apparatus. “I take that personally. My entire presidency has been about helping working families. I’ve been working too hard at this. I’ve got some of those folks who are saying this stuff after all I’ve done to help lift their industries up.”

It is a frustrating reversal of fortune for Obama, who was embraced in 2008 as the progressive darling of “hope and change.” Now, even his former secretary of state, Hillary Rodham Clinton, whom progressives abandoned in the 2008 primary, hedged recently in her support for the TPP as she lurches to the left to shore up support from the base ahead of her 2016 campaign.

Obama’s exasperation was apparent last week as he amped up efforts to win over his liberal base during a series of events, including a small-business roundtable in Northern Virginia broadcast on MSNBC and an unannounced appearance on a conference call between Labor Secretary Thomas Perez and liberal columnists.

Taking direct aim at Warren and other Democrats opposed to the trade pact, Obama called claims that the administration has negotiated the terms of the deal in secret “dishonest.”

“It’s concerning when I see friends of mine resorting to these kinds of tactics,” Obama said, according to an account from Washington Post columnist Greg Sargent, who was on the call.

“I’m not adverse to continuing to engage with members of Congress or unions or anybody else in the progressive community about how we can make sure this is the strongest agreement possible,” Obama concluded. “But what I am adverse to is a bunch of ad hominem attacks and misinformation that stirs up the base but ultimately doesn’t serve them well. And I’m going to be pushing back very hard if I keep on hearing that.”

Major free-trade pacts such as the TPP always have multiple aims for U.S. presidents. Until recently, Obama focused on the deal’s geopolitical implications, making the case that it would help the United States become more integrated into the economy of the Asia-Pacific region and force China, whose economic clout has grown rapidly, to play by clearly defined, U.S.-backed rules of international commerce.

In previous years, Obama talked about the TPP only rarely — mostly during his trips to Asia — and aimed his pitch at audiences inclined to be moved by such strategic concerns: national security hawks, business groups, foreign leaders eager for U.S. economic assistance.

But with the TPP reaching its endgame — negotiations between the U.S. and 11 other nations are nearing conclusion — Obama has had little choice but to turn the argument toward the U.S. economy.

Advisers had hoped that recent signs of economic health — a bullish stock market, falling unemployment — would make Americans more amenable to the president’s pitch on trade. He and his allies have argued that
95 percent of the potential market for U.S. goods lives outside the country and that ignoring Asia would be ceding the fastest-growing market in the world.

Noting that trade opponents often cite the affects of the 1993 North American Free Trade Agreement, which labor unions blame for killing hundreds of thousands of jobs, Obama told his OFA audience: “I’m thinking, ‘I just came out of law school when NAFTA was passed.’ That’s not the trade agreement I’m passing. You need to tell me what’s wrong with this trade agreement, not one that was passed 25 years ago.”

Obama went so far as to mockingly compare some of the criticisms from the left to the complaints from conservatives that his health-care law, passed in 2010, would result in government-sanctioned “death panels.”

His opponents on the left, who have been preparing for this moment for months, have been quick off the mark with an aggressive campaign to stop the deal in its tracks. And as the rhetoric has escalated, they have begun turning Obama’s words against him.

“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,” Charles Chamberlain, executive director of Democracy for America, said in a statement. “Frankly, it’s beneath this president to resort to such name-

Asked about Chamberlain’s comment, White House press secretary Josh Earnest cited a CNN poll last week that found Obama’s approval ratings among liberals had risen from 90 percent in March to 97 percent.

But there is little question the criticism has irritated the president. During his OFA appearance, Obama scoffed at the contention that the trade pact would kill jobs and exacerbate the income gap.

“By this logic,” he said, “I would have had to do all this stuff for the last six and a half years, and then, suddenly, just say, ‘Well, I want to just destroy all of that.’ Does that make sense?”

“No,” someone shouted.

“Right answer,” Obama replied. “It does not.”