The American Postal Workers Union, which numbers more than 200,000 United States Postal Service employees and retirees, announced its endorsement of Sanders Thursday morning. The APWU nod comes after the union’s National Executive Board voted last week in favor of the Vermont senator.

“Politics as usual has not worked,” APWU president Mark Dimondstein said in a press release. “Enough is enough!” The union lauded Sanders for his history of advocating reform for the public mailing service in the face of a financial crisis, as well as protecting it from cuts and privatization.

The endorsement from the APWU marks Sanders’ second, and largest, union thumbs-up so far. National Nurses United, the biggest nurses’ labor union in the country, voted to endorse the candidate in October. Some of the nation’s most influential labor unions, including the International Brotherhood of Teamsters, the Service Employees International Union, and the AFL-CIO, have yet to choose their candidate, according to The Hill.

The APWU also cited Sanders’ broader advocacy for labor, pointing to his record of rallying for workers’ rights, free community college tuition, and a higher minimum wage. “No other candidate has his record of exposing the rule of the billionaire class,” Dimondstein said. “Sanders is refusing all corporate money. He doesn’t have a ‘super-PAC.'”