Murray said a vote for Republican Dino Rossi is a vote for the failed policies of former President George W. Bush. Rossi declared that he would put Washington, D.C., on "a pork-free diet" and end what he calls a reckless pursuit of federal money by Murray in her 18 years in the Senate.

Murray and Rossi easily won Washington's primary Tuesday on a day in which President Barack Obama came to the state to campaign for the Democrat.

Obama's presence shows how high the stakes are. Republicans will likely need to oust Murray if they want take back control of the Senate.

Two other states held elections Tuesday, including a tight GOP gubernatorial primary in Wyoming and a closely watched special legislative race along the California coast.

With about 59 percent of the expected vote counted, Murray had 46 percent, compared with Rossi's 34 percent. GOP hopeful Clint Didier, a former Super Bowl winner for the Washington Redskins who has the backing of tea party activists and Sarah Palin, was running a distant third with 12 percent.

The results signal how close the race might be for Murray. The fact that a three-term senator is not able to pull a majority of the vote shows her vulnerability, but she could gain ground in November when the Democratic base is more motivated than in a primary that was essentially a foregone conclusion.

Murray said she has been underestimated "all my life. And that's just fine, thank you."

Murray has built a reputation as an underdog ever since she was told by a politician early in her career she was just "a mom in tennis shoes" who couldn't amount to much. The quote inspired her to get into politics and has been her catch phrase in past campaigns.

Rossi, a real estate investor who narrowly lost bids for governor in 2004 and 2008, has been attacking Murray over her efforts to bring home federal dollars at a time when the debt is soaring, and over her votes on the financial regulation bill. He said Murray embodies the wasteful spending that is so prevalent in Washington, D.C.

"People understand that we're spending too much money," Rossi said. "They know that you can't keep borrowing from the Chinese and Saudis and printing money and expect all that to pan out just fine, because it won't."

Murray, who is fourth in Senate Democratic leadership, says her experience and clout make her the right candidate for the job, and that Rossi represents a return to the Bush era.

"I think that the people of our state, and really our country, don't want us to go back to what we had. We're taking the hard steps forward." Murray said. "Are we there yet? No. But we are working hard every day, and I know what we need to do."

In Wyoming, former U.S. Attorney Matt Mead narrowly led state auditor and Sarah Palin-backed Rita Meyer in the GOP gubernatorial primary. The winner will be favored to win in November and help the GOP pick up a governor's seat, with popular Democratic Gov. Dave Freudenthal stepping down after two terms.

Mead held a 714-vote lead out of 105,000 votes cast. The winner will face Wyoming Democratic Party chairwoman Leslie Petersen.

In California, a normally quiet legislative special election turned into a bigger deal because a Democratic victory could have put the party within one vote of the two-thirds majority they need in the Senate to approve budgets and tax increases.

The Republican won despite an endorsement for the Democrat by Obama, who said the ability of Republican state lawmakers to block the spending plans of majority Democrats is equivalent to the roadblocks he has faced in Congress.