DENVER - Mitt Romney's performance in the first presidential debate was considered a game changer. That may be particularly true here in the Rockies.

When Romney took to the debate stage here at the University of Denver on Oct. 3 to face President Obama for the first time, the Republican nominee's bid for the White House was on the brink of collapse. Ninety minutes later, the Romney campaign was infused with a new energy. In the weeks that followed, he nearly erased Obama's lead in the state. And now, less than a week from Election Day, Romney has made Colorado a tossup.

"I think it's only natural that events have an outsized impact the closer to home they happen," said Eric Sondermann, a Denver-based political analyst. "While the Denver debate was a turning point, if not the turning point of the campaign nationally; it was also magnified locally."

Obama was up by as much as 6 percentage points in Colorado in September. But that momentum all but vanished in October as Romney seized front-runner status in several polls.

"The location of the debate was, for us, a great benefit. It was really a national groundswell that developed out of that, and we're a product of that here in Colorado," said Romney spokesman Chris Walker. "We felt good about our energy, but it just got kicked into a higher gear after that."

In 2008, Colorado was a case study of Obama's ability to overhaul the electoral map: He won the state by 9 percentage points, even though Republican George W. Bush posted a 5 percent margin of victory only four years earlier.

To swing Colorado from red to blue, Obama ran up large vote totals in traditional Democratic strongholds like Denver and Boulder while snatching votes from John McCain in the state's more conservative areas.

"He was winning everywhere except in the most conservative places, and even there he was cutting into the margins," Sondermann said.

Along with the debate, analysts say Colorado's persistently high unemployment rate has hindered Obama. The current jobless figure of 8 percent is slightly above the national average and 1.4 percent higher than it was when Obama took office.

The state's centrist mind-set -- its Democratic governor is fiscally conservative and socially liberal -- also isn't helping Obama.

"The Democrats who thrive out here have figured out how to operate in an independent streak," Sondermann said. "Obama hasn't."

Despite Romney's surge, the Obama campaign insists the president will ultimately prevail in Colorado.

"Our grassroots campaign is going to make the difference," said spokeswoman Kim Parker. "We never left Colorado after the 2008 election and have maintained an ongoing conversation with voters ever since then."

In the campaign's closing days, both sides are pouring resources into the state, whose nine electoral votes could play an enormous role in deciding the presidency as the nation sprints toward what could be one of the closest elections in U.S. history.

Obama is scheduled to appear in Boulder on Thursday, the same day Rep. Paul Ryan, Romney's running mate, will speak in northeast Colorado. Romney will visit the Denver area on Saturday.

Rep. Diana DeGette, a Colorado Democrat, acknowledged the stakes.

"This race really could just come down to Colorado," she said. "And this race really could just come down to a few votes."