With Washington's Republican precinct caucuses coming up Saturday, the state's highest profile Republican official is keeping mum on which presidential candidate he's backing.

Attorney General Rob McKenna says he won't be offering any endorsements because he wants to concentrate on his gubernatorial campaign.

"Rob is focused on his race. He wants to spend all his time and energy making sure this is a successful campaign," said McKenna spokesman Charles McCray. He said McKenna will visit several caucuses Saturday to promote his own candidacy.

In an interview with POLITICO, McKenna said candidates for office shouldn't take sides in other races. "The rule is you stay out of other people's primaries," he said.

McKenna's "rule" must be a new one. It certainly didn't stop him from jumping out early to endorse John McCain in the 2008 presidential race.

McKenna endorsed McCain in February of 2007 and served as the senator's state campaign chairman and stood with him at local campaign rallies.

But McKenna's campaign says he won't be doing the same for Mitt Romney, Rick Santorum or anyone else prior to this year's caucuses.

Democrats have sought to embarrass McKenna over his silence, saying he's afraid to be linked closely to any of the national GOP contenders.

"He's hiding who he really supports - otherwise he would have to tell voters how his positions line up with Santorum, Romney and the rest of the GOP slate," said state Democratic Party spokeswoman Reesa Kossoff.

Four years ago, it was the Democratic presidential race that was more unsettled heading into the Washington caucuses, when Gov. Chris Gregoire endorsed candidate Barack Obama, splitting with Sens. Patty Murray and Maria Cantwell, who backed Hillary Clinton.

State Republican Party Chairman Kirby Wilbur praised McKenna's neutrality as smart given the uncertain picture in 2012.

"There is no clear-cut nominee - he would have to work with whoever gets the nomination. There is no need to alienate any one of the four," Wilbur said.