GRAND JUNCTION, Colo. - Republican Mitt Romney on Tuesday told voters in western Colorado's largest city that President Obama's tax plan is a "kick in the gut" for a nation that fell further behind because of the administration's liberal policies.

Romney assailed Obama on the economy, citing a recent dismal jobs report in a rousing pitch to nearly 1,000 people packed into a small gymnasium in a heavily Republican area hit hard by the economic downturn. Colorado, Romney told them, "can well be the place that decides who your next president is going to be."

But even as he made his appeal to the state's swing voters, Romney's campaign remained relatively low-key Tuesday and he has yet to make his way to Denver, the state's population center, which helped propel Obama to victory by 9 percentage points in 2008.

After leaving Grand Junction, Romney headed to a Colorado Springs food bank that's aiding victims of the massive Waldo Canyon fire. He helped volunteers there check expiration dates on boxes of macaroni and cheese and bulk packages of beef ramen noodles.

"It's been an inspirational thing to see how people have stepped up to make a difference," Romney said after tearing open a carton of mac 'n' cheese with his teeth to inspect each box inside.

In Grand Junction, the Romney campaign chose the school's smaller gymnasium, but probably could have filled a larger one next door, as hundreds gathered in an overflow spot on the lawn outside.

"This is a good venue for the whole Western Slope," state Attorney General John Suthers, head of Romney's Colorado campaign, told The Washington Examiner. "It's a smart place to campaign to energize voters."

Romney, who returned to the campaign trail after a week's vacation, tore into Obama's plan to extend expiring tax cuts only those earning less than $250,000 annually.

"For American job creators and small businesses, he's announced a massive tax increase," Romney said.

Romney's reception in Colorado was largely enthusiastic, with the crowd wildly cheering his plans to lower taxes, reduce government spending and repeal Obama's health care reforms.

"This old-style liberalism of bigger and bigger government and bigger and bigger taxes has got to end," Romney said, "and we will end it in November."

One audience member questioned how Romney could challenge Obama's health care law when Romney, as governor of Massachusetts, instituted similar reforms. Romney suggested that states, rather than the federal government, should be tackling such difficult issues.

"I sure hope the president brings it up because I'll point out the differences between what we did and what he did," Romney said. "States are the places where we make we decisions that affect the lives of people and I like that idea."

Even while some of his fellow Republicans have questioned the level of enthusiasm for Romney, those who turned out to hear the presumptive Republican presidential nominee Tuesday left little doubt that they'll back the man who could prevent Obama from winning a second term.

"Obama wants to take us down a more socialist track where government controls every aspect of our lives," Colorado resident Jackie Sequi-Edelmann said after the speech. "I like Romney's stance on the economy and his family. I think he's going to win in a landslide."