Maine Democrat Platner wins Senate primary as 4 states vote

Maine Democrat Graham Platner won his party's US Senate primary on Tuesday, setting up a November contest against Republican Sen. Susan Collins, as voters in four states cast ballots in key gubernatorial, Senate and congressional races.

Platner won 72% of the vote after Gov. Janet Mills withdrew from the race in April. Mills remained on the ballot and received 19.6% with 72% of votes tallied, according to the Associated Press (AP). Collins ran unopposed in the Republican primary.

Maine's gubernatorial primaries remained too close to call, with several candidates clustered near the top of both parties' fields. The AP had not called the races because the state uses ranked-choice voting, under which voters rank candidates by preference and votes are redistributed until a candidate secures a majority.

In South Carolina, Republican Sen. Lindsey Graham won renomination with 56.8% and will face Democrat Annie Andrews in November. The Republican gubernatorial primary advanced to a runoff between Lt. Gov. Pamela Evette and Attorney General Alan Wilson after neither candidate secured a majority.

Rep. Jim Clyburn easily won the Democratic nomination in South Carolina's 6th Congressional District, while a crowded race to succeed departing Rep. Nancy Mace in the 1st District headed to runoffs in both parties.

In Nevada, Republican Gov. Joe Lombardo and Democratic Attorney General Aaron Ford won their parties' gubernatorial nominations. Several congressional races remained unresolved, including the Republican primary in the open Second District seat.

In North Dakota, Republican Rep. Julie Fedorchak won renomination in the state's lone US House district and will face Democrat Trygve Hammer in November.