WASHINGTON - A Washington state victory in hand, Mitt Romney is looking ahead to Tuesday's 10-state bonanza that features contests from Alaska to Ohio to Massachusetts, millions in campaign spending and the largest single day of voting yet in the Republicans' topsy-turvy primary race.

The former Massachusetts governor won Saturday night's low-turnout caucuses, adding another win to his tally and gaining momentum in his drive to the GOP nomination. Leading in delegates to the GOP's national convention, Romney looked to defend his front-runner standing even while rivals Rick Santorum, Newt Gingrich and Ron Paul sought to keep their candidacies afloat.

"The voters of Washington have sent a signal that they do not want a Washington insider in the White House. They want a conservative businessman who understands the private sector and knows how to get the federal government out of the way so that the economy can once again grow vigorously," Romney said in a statement Saturday night before heading to Sunday campaign stops in Georgia and Tennessee.

Rick Santorum, in search of his first wins since Feb. 7, urged Ohio Republicans not to heed those who cast Romney as the inevitable nominee. He said the race was far from over, even as he was locked in a tight race in Washington state for second place with Paul.

"We need someone who can go out and make the case, not with the most money, but with the best ideas, the best vision, the best track record," Santorum said in Bowling Green, Ohio. "Go out and make this election about big things."

Santorum planned a Sunday appearance on "Fox News Sunday" before campaigning in Tennessee and Oklahoma, two states that could turn around his struggling, rag-tag campaign. He is far outpaced in organization and it's not clear he even has paid staff on the ground in the upcoming states.

Meanwhile, Gingrich looked to blitz the Sunday talk shows, appearing on four national morning programs but planned no campaign events with actual voters, reflecting his strategy of using media appearances to offset his advertising and organizational disadvantages. Gingrich, leading in the polls in his home state of Georgia, is looking for his first victory since his lone win in South Carolina on Jan. 21.

Speaking on CNN's "State of the Union" program, Gingrich said Sunday he was confident he would win "a very, very decisive victory" in Georgia.

"We're going to do pretty well, I think, in Tennessee and Oklahoma and Ohio and a number of other states," he added.

Gingrich has cast the Georgia showdown as a do-or-die day for his struggling campaign.

With contests in 10 states and 419 delegates up for grabs, Tuesday was shaping up to be a hard-fought day that could settle -- or shuffle -- the quest for the Republican nomination.

There also are primaries in Massachusetts, where Romney was governor, and Virginia, where Gingrich and Santorum failed to qualify for the ballot. Other contests are in Vermont, North Dakota and Idaho.