LONE TREE, Colo. -- Certain to lose in Florida, Republican presidential candidates Rick Santorum and Ron Paul courted voters Tuesday in Western states that hold upcoming contests -- and made clear they're not bowing out.

"No matter what happens in Florida, this race is wide open," Santorum said in this town outside of Denver, casting the fight for the GOP nomination as a long slog. "We plan on being in this campaign for a while."

In a separate appearance, Paul ignored Florida's primary Tuesday as he spoke to more than 1,000 supporters in Fort Collins, many of them students at Colorado State University.

The libertarian-leaning Texas congressman focused on his bedrock issues -- cutting spending and upholding the Constitution.

"All we have to do is return to our constitutional form of government, and we can get out of this mess in no time," said Paul, garnering loud cheers for a blast at U.S. foreign policy. "We need to keep America safe, but not to be the policeman of the world."

Both candidates started the day in Colorado, which will hold caucuses Feb. 7, and were ending it in Nevada, which will hold caucuses Saturday.

"You're going to hear Governor Romney's going to win Florida," which he did handily. "You're going to hear the race is over," Santorum told tea partyers in Las Vegas as early tallies started to be released in Florida. "But the race is just getting started. It's going to go back and forth."

Conceding Florida to Mitt Romney and Newt Gingrich, Santorum and Paul headed West to try to lay the groundwork for upcoming contests.

"If you don't like the way the race is going right now, just wait a week or two," Santorum told a 300-person crowd in the Denver suburb of Lone Tree. "You have a chance to change this race. You have a chance to put up a conservative who can win."

Santorum raised more than $4 million since his surprise showing in Iowa, and aides said he had more than $1 million in the bank. He started spending some of that on television ads in Colorado and Nevada with an ad that likened Gingrich's views to President Barack Obama and House Democratic leader Nancy Pelosi.

"Who are these three cap-and-trade-loving, bailout-supporting, soft-on-immigration, big-government-mandating politicians?" the announcer asks in the minute-long ad.

In person, Santorum said criticism of Romney's and Gingrich's wealth was misguided, and only helps Democrats, but then turned caustic.

"We cannot have leaders who are unpredictable or lack the conviction to do what's necessary," he said of Gingrich.

One voter asked Santorum to make a campaign issue out of Gingrich's three marriages.

Santorum said Gingrich had been open about his past, but allowed that "character matters.

"It's the issue of trust. Do you trust somebody who has done things that you question, whether it's in their personal life or professional life?" he said.

But he also said people can learn from their mistakes.

"Our job is to forgive people if they ask for forgiveness," Santorum said. "I don't question the sincerity of his repentance."