In Indiana, where Republicans hold a supermajority in both chambers of the state legislature and most top offices are held by GOP politicians, the May 7 primary will determine the outcome of the general election in many races.
The most-watched is the GOP race for governor, a six-way competition of office-seekers who all have cast themselves as outsiders in an appeal to conservative voters.
Indiana also will send at least three new representatives to the U.S. House following a series of retirements.
Live election results will begin tabulating after polls close at 6 p.m. local time.
President
Governor
U.S. Senate