AFL-CIO President Richard Trumka warned Democrats on Wednesday that they could not take union endorsements for granted and would have to meet a higher bar this election cycle to get them. The leader of the nation's largest labor federation also urged Republicans to try to win union endorsements, saying it was possible if they backed unions in key issues.

"Being a Democrat is not a qualification for our endorsement, and being a Republican isn’t a disqualifier," Trumka said at an event hosted by the Iowa Federation of Labor. "Simply put: It doesn’t matter if there’s a D, R, or I next to your name. If you support us, and I mean really support us, we will support you. But you better come with more than platitudes and a party label."

Trumka added, "It means visiting our worksites and our union halls. It means marching on our picket lines. It means learning about our hopes and dreams and understanding our concerns. It means being just as pro-union when you’re at the Farm Bureau and the Chamber of Commerce as you are here today."

Unions are major sources of campaign-related spending. Organized labor overall poured an estimated $219 million into the last presidential election cycle, according to the Center for Responsive Politics. Of that, 88% was either donated to Democrats or spent on their behalf. Only 12% of the union spending benefited Republicans.

President Trump has strong appeal in many sectors of labor. Trumka said in 2017 that Trump benefited from a 13-point swing in support from union members over the 2012 GOP candidate, Mitt Romney.