Voters cast their ballots at a polling place at Cromie Elementary School in Warren, Mich., in March. Warren is in Macomb County, considered a critical suburb in the presidential election.

WARREN, MI – MARCH 10: Voters cast their ballots at a polling place at Cromie Elementary School on March 10, 2020 in Warren, Michigan. Michigan is one of six states voting in the presidential primary today. (Photo by Elaine Cromie/Getty Images)