Hillary Rodham Clinton has won the endorsement of the American Federation of Teachers. It's the first major labor union to make an endorsement in the 2016 presidential campaign.

Randi Weingarten, the president of the union, says in a statement Saturday that Clinton is the "champion working families need in the White House."

The endorsement was widely expected. The teachers' union supported Clinton's primary campaign in 2008 and Weingarten is a longtime Clinton ally.

The AFT represents more than 1.6 million members nationwide, including K-12 teachers and school personnel, higher education faculty and staff, early childhood educators and retirees.