The midterm elections officially begin on Tuesday with primaries in Texas, North Carolina and Arkansas. As war with Iran breaks out, Democrats and Republicans are figuring out who they want to lead their party into November’s general election, when control of Congress and statehouses around the country will be up for grabs.

The most hotly contested races of the day are in Texas, with fierce competition on both sides of the aisle for U.S. Senate nominations. It’s possible that the Republican campaign will continue into a runoff. Some voters in two major Texas counties are being turned away at polling locations and directed to different voting precincts, causing confusion and frustration.