Richard Trumka, AFL-CIO president, thinks union voters will firmly reject The Donald if wins the GOP presidential nod. (Photo by Jonathan Newton/The Washington Post)

There’s a debate among union leaders over whether Donald Trump’s candidacy will repel or attract the millions of  American union voters who help sway elections from the top of the ballot to the bottom.

But AFL-CIO President Richard Trumka is not on the fence, or on the “wall” in Trumpese, about how Trump’s candidacy should affect his 11.6 million members: Trump should be soundly rejected if he’s the GOP nominee in favor of the Democratic candidate.

“Donald Trump says we make too much money already and he wants to lower our wages,” Trumka said said in an interview after addressing House Democrats’ retreat in Baltimore last week.  “If you watch a Democratic debate, they talk about issues that affect people. If you watch the Republican debate, it’s bickering about who can exclude the most people from this country.”

As the head of the country’s largest labor union, Trumka preaches what he believes is the key to Democrats increasing their numbers at the ballot box in November: a message of narrowing income inequality.

“All of the candidates, including the Republican candidates are talking about inequality and opportunity,” he said. “The question now becomes what’s the solution.”

After years of declining membership and shrinking influence, labor leaders are working aggressively to get their issues — higher wages, expanding worker protections and increasing benefits — on the campaign table in 2016, Trump or no Trump. They’ve succeeded in becoming part of the conversation as the income inequality refrain is frequently echoed on the campaign trail from Democrats — and some Republicans — as well as on Capitol Hill.

Democrats generally agree that focusing on economic opportunity is a winning bet, but the recent drive for a more progressive party message hasn’t been well received by all. Tensions among Democrats over labor priorities led to a tense showdown between union leaders and moderate Democrats during last summer’s debate over trade negotiating authority. And Trumka is still angry at some House Democrats he believes “lied” to him during the fast-track vote, saying union support for them is off the table.

Trumka said the AFL-CIO’s political strategy started coming together during a wage summit held last January. Labor leaders drafted a list of issues for the coming election and crafted a strategy for electing pro-union Democrats at every level of government, from state and local races up to president.

The AFL-CIO has not officially endorsed in the presidential contest. Trumka said the union could endorse at its annual winter summit later this month but nothing has been decided, adding there is strong support for all three Democratic candidates, but the union could remain neutral in the primary contest too.

“No matter who wins on the Democratic side, they’re going to have a progressive economic agenda that is going to force the Republicans to talk about it,” Trumka said.

At the summit, the AFL-CIO adopted a list of policy priorities including better public education, improved retirement options, equal pay, paid leave and more union protections it hoped would frame the 2016 conversation.

Some of those issues have been adopted by Democrats on the campaign trail, most prominently by Sen. Bernie Sanders. The self-described democratic socialist has built his brand around union-friendly messaging on income inequality while his opponents — Hillary Clinton and Martin O’Malley — also tout pro-worker platforms.

Trumka believes that makes it even easier to set up the simple message that Democrats are the party of workers and Republicans are the party of Trump.

“When a frontrunner for the top candidate in a party is talking about excluding a whole group of people because of their religion, that is dangerous,” he said. “To me it doesn’t matter if it’s Ben Carson or Trump. If they are being divisive and racist and fully of bigotry, I’m going to fight against it.”

But not all union leaders think their workers will automatically renounce Trump — who is drawing unusual support from working-class voters (it remains to be seen whether that can be expanded beyond Republicans). That’s because the business mogul openly speaks to their economic anxieties and has bashed the Trans-Pacific Trade Partnership, threatened to keep undocumented immigrants out of the country by building a wall and pledged to stop eating Oreos because their producer, Nabisco, moved some production to Mexico.

But Trumka thinks workers will reject Trump if he wins the GOP nod.

“When a candidate comes out and says all we have to do is build a wall around the United States and everything is going to be great, American workers are saying ‘Really?,’” he said. “Democrats are moving to solutions…Five million union workers negotiated contract raises last year.”

Though Democrats are their most consistent ally, Trumka has demonstrated that labor is not afraid of strong arming and punishing Democrats who threaten its goals.

The AFL-CIO was part of a scorched-earth campaign last summer against a handful of Democrats who supported fast-track authority allowing President Obama to finish work on the long-sought TPP agreement. Labor groups oppose the trade deal, which they say will drive down U.S. wages by flooding the market with cheap goods made by underpaid workers.

Trumka and his allies organized relentless call-in efforts and ad campaigns to pressure Democrats to oppose fast-track. The labor leader also threatened to court primary opponents against Democrats who defied them.

The aggressive drive included an ad buy worth more than $80,000 attacking Rep. Ami Bera (D-Calif.) for supporting the trade legislation and rallies outside the district offices of Reps. Brad Ashford (D-Neb.), Susan Davis (D-Calif.) and Scott Peters (D-Calif.).

But fast track passed the House, 218 to 208, in June — with the support of 28 Democrats. Trumka said that fight is in the past and he is now focused on defeating TPP, which likely won’t come up for a congressional vote until after the elections. But that doesn’t mean every Democrat who voted for fast track is off the hook.

“There are a couple that actually lied to us and that’s unacceptable under any circumstances and we won’t support those couple again,” he said.

So far, no union-picked primary challengers have emerged in those races. But Trumka wouldn’t rule out any options.

“We’re still working through it,” he said. “I don’t make those decisions unilaterally, a lot of people think I do. But I really try to work with the people on the ground who are most affected and have them make those decisions.”