Former Vice President Joe Biden received an unexpected endorsement Monday from Michael C. Taylor, the Republican Mayor of Sterling Heights, Michigan. Taylor voted for Donald Trump in the 2016 election.

"I think Joe Biden is the candidate who can unify all of the Democrats, and he's the candidate who can appeal to moderates and Republicans like me who don't want to see four more years of President Trump," Taylor told the Chicago Tribune.

Six states, including Michigan, are holding Democratic primaries Tuesday. Michigan is the biggest prize of the day, awarding 125 pledged delegates. A recent poll from Monmouth University on Monday showed Biden with a 15-point lead over Sanders in the state.

Michigan is important for Biden’s main Democratic opponent, Vermont Sen. Bernie Sanders. Sanders is relying on support from disaffected working-class voters in order to win the state and rejuvenate his campaign. Sanders also hopes to turn out young progressive voters in cities such as Ann Arbor.

Yet, Biden has won endorsements from vital figures in the state, such as Gov. Gretchen Whitmer. He has also been picking up support from unions, which typically favor Sanders. In addition, Biden has had strong support with African-Americans, who make up around 14% of Michigan’s population.

Michigan is expected to play a major role in November as a "swing state." Democrats are hoping to flip the state back to blue after Trump edged Hillary Clinton by fewer than 11,000 votes.

An endorsement from Taylor could boost Biden's chances in the general election. Sterling Heights is Detroit's second-largest suburb with a population of roughly 130,000.