On June 9, voters in Maine, South Carolina, Nevada, and North Dakota went to the polls. In Maine, voters selected oysterman and military veteran Graham Platner—a dark horse candidate who won the race after Gov. Janet Mills suspended her Senate primary campaign—to take on incumbent Sen. Susan Collins (R-Maine), a long-serving political juggernaut in the state who ran unopposed for her party’s nomination on Tuesday. In South Carolina, two state leaders outpaced two sitting members of Congress to advance to a runoff for the Republican gubernatorial nomination. Meanwhile, voters in Nevada made their pick for governor in a race that has drawn national attention as Democrats seek to take the seat back and Republicans seek to hold onto their gains from recent years....