On August 7, Montana Democratic Party nominee John Walsh, running for re-election to the U.S. Senate, dropped out of the race. The Democratic Party will choose a new nominee by August 20. Walsh had been renominated in the June 3, 2014 primary. See this story.
If Montana had California’s top-two system, and if Walsh had placed first or second in the June 2014 primary, he would not be allowed to withdraw and he would be one of only two names on the November ballot.