(CNN) - Voters in Washington state and Wyoming hold primaries Tuesday, with the Senate contest in Washington and a battle for the open Wyoming governor's seat the most closely watched races of the day.
In Washington, Democratic Sen. Patty Murray and Republican candidate Dino Rossi are expected to emerge from a crowded primary field, setting up a November showdown. Under the state's system, the two candidates who receive the most votes regardless of party affiliation move on to the general election. Voting has been underway for two weeks, with Washington primarily a mail-in ballot state.
In many ways, Murray and Rossi have already begun their general election campaigns, focusing their attacks on each other. Polls show a close race in the fall if they both advance.