AFL-CIO President Richard L. Trumka on Monday accused Donald Trump of peddling deceit on trade issues, calling the presumptive Republican presidential nominee the “king” of outsourcing labor abroad for his personal business.

“Look at what he does, not what he says,” Trumka said in an interview in his office overlooking the White House. “He could have an effect on trade by bringing all the products he makes overseas back home and have Americans produce them. But he doesn’t do that. Like every other person out there, he takes advantage of a bad system that hurts workers and helps people at the top. He’s the king of doing that.”

Trumka’s remarks make clear that the nation’s largest collection of labor unions, with 12.7 million members, plans to actively campaign against Trump despite the candidate’s fierce public opposition to free-trade pacts, which largely echoes the AFL-CIO’s position. Trump has vowed to back out of the 12-nation Trans-Pacific Partnership (TPP) trade accord negotiated by the Obama administration.

On Tuesday, the AFL-CIO will hold its first-ever trade conference in Washington featuring a video message from Nobel Prize-winning economist Joseph Stiglitz and a keynote address from Sen. Sherrod Brown (D-Ohio), who both oppose the TPP. Stiglitz called it the “worst trade deal ever.”

Trump has “successfully tapped into the anger and frustration that’s out there,” Trumka said. “But he will not make it better; he’ll make it worse. He won’t solve the problem; he really is the problem.”

On Monday afternoon, the labor leader posted a Twitter message linking to a Washington Post story from March about Trump’s offshore manufacturing for his men’s clothing line. “@realDonaldTrump & I are both speaking on trade tmrrw, but only one of us has personally profited off outsourcing,” Trumka wrote.

Trump used his anti-free-trade rhetoric to appeal to Republican primary voters who have expressed economic anxiety in the face of a growing wage gap and concerns that international trade deals have benefited corporations and Wall Street.

President Obama has touted the TPP as a way to embed the United States more firmly into fast-growing markets in Asia at a time of rising competition with China. But studies have shown only a tiny economic impact for the U.S. economy.

Under pressure from the left in the Democratic primaries, Hillary Clinton, the presumptive nominee, announced opposition to the TPP even though she was a chief proponent while serving as U.S. secretary of state in Obama’s first term.

Trumka said he believed her position is sincere. “She’s against TPP,” he said. “She supports our position. What else can she do? Say, ‘I’m really against it?’ ”

White House officials view a potential lame-duck session of Congress after the November elections as a final chance for Congress to ratify the TPP.

Some analysts have said they believe Clinton would not stand in the way. Trumka disagreed.

“If she gave a wink and nod, she would start off her presidency in the hole by losing a vast majority of those who have supported her,” he said. “She’s too smart, too committed, and I believe she has too much resolve to make that kind of stupid mistake.”