COLUMBUS, Ohio (AP) — Democratic U.S. Sen. Sherrod Brown has landed the endorsement of the United Auto Workers a year after Ohio Democrats saw a series of labor unions abandon their Senate candidate for his Republican opponent.

The UAW's backing of Brown is hardly a surprise. Brown and labor are longtime allies. In a video released Monday to accompany the endorsement, Brown thanked the UAW and credited them with leading the creation of the American middle class.

Yet the unusual 2016 election threw many previously predictable political patterns into question — and not just at the presidential level.

Democratic ex-Gov. Ted Strickland saw several big labor unions — including the Teamsters, International Union of Operating Engineers and the United Mine Workers — shift their past support from him to Republican U.S. Sen. Rob Portman during the last cycle.

The Mine Workers' defection hit Strickland, a native of coal country, particularly hard. It was attributed with helping Portman score a victory for Republicans in a state whose close political divide appeared initially to give Strickland a strong chance of unseating him.

The UAW's support sets up Brown for a repeat showdown with Republican rival Josh Mandel, the Ohio state treasurer, on the issue for the 2008 auto industry bailout. Brown supported the rescue, and Mandel says he would have opposed it. Mandel must defeat Cleveland business executive Mike Gibbons in next year's Republican primary to gain a rematch against Brown next fall.

During a debate in 2012, Mandel called Brown "the bailout senator." Brown said there were so many auto assembly and parts plants employing people in Ohio that Mandel's position "just boggles my mind."

A spokeswoman for Mandel's campaign called Brown a "career politician" with "radical left-wing views" that are out of step with Ohio workers.

"Over his 24-year career in Washington, Brown has voted for tax increases, supported (former President Barack) Obama's war on coal and spending sprees, all of which have destroyed Ohio jobs and hurt our families," said spokeswoman Erica Nurnberg.

UAW Region 2B currently represents 150,000 active and retired members in Ohio. Its director, Rich Rankin, said the union supports Brown because he stood with the auto industry and because he "recognizes that we need to invest in our workers and restore the value of work in our country."