1 of 3
Gerald Herbert, Associated Press
Republican presidential candidate, former Massachusetts Gov. Mitt Romney greets supporters at a campaign rally in Cleveland, Friday, March 2, 2012.

WILMINGTON, Ohio — Republican voters in Washington state are set to choose a presidential favorite as the GOP hopefuls focus on the 10 contests on Super Tuesday.

All four contenders have visited Washington ahead of Saturday's caucuses, but three of the four are campaigning in Ohio, the critical primary next week

Mitt Romney, Rick Santorum and Newt Gingrich are fighting for Ohio — and it promises to be another important test for Romney as he seeks to quell doubts about his candidacy among voters and the party establishment.

Washington's caucuses are the last before the Super Tuesday contests that offer a total of 419 delegates.

The caucuses are an opportunity for Ron Paul. He's the only candidate on the air, having spent roughly $40,000 to run ads on cable channels.