Colorado voters picked President Barack Obama on Tuesday, the first time the state backed a Democratic presidential candidate for a second term in 76 years.

A massive Obama get-out-the-vote effort executed through a combination of cutting-edge technology and old-fashioned boots on the ground turned out women, Latinos and young voters to help push the president over the finish line.

His win over Republican presidential nominee Mitt Romney came despite suffering a major setback last month when he was trounced by Romney during the first presidential debate at the University of Denver and even though exit polls showed that the No. 1 issue facing the country was the sluggish economy.

Colorado, which has nine electoral votes, was the scene of one of the most intense swing-state battles in the country. This year, the candidates and their running mates made roughly 45 campaign stops in Colorado.

The Democratic headquarters in downtown Denver was alight with energy and cheering as large television screens projected victories not only for Obama, but for a handful of Senate seats across the country.

“Obama won Colorado because he says the same things in red parts of the country as he does blue parts of this country,” said Sen. Michael Bennet.

“Let’s work to turn Colorado from purple to blue,” said Rep. Diana DeGette, D-Denver, who handily won re-election Tuesday.

Gov. John Hickenlooper struck a less partisan tone, saying that people need to go forward as one nation. “Let’s lead this country forward,” he said. “The first step of that journey starts tomorrow.”

And Denver Mayor Michael Hancock said he never underestimates “the wisdom of the voters in Colorado.”

“We’ve done a lot of work. It’s been a good night for Denver, a good night for the state and a good night for the country,” he said. “Tomorrow we go to work and implement the will of the voters.”

At Sports Authority Field at Mile High, where Colorado Republicans awaited election returns, energy began to wane early in the night, when a string of small swing states swung for Obama. “We’ve got to keep the faith,” the lead singer of the live band brought in to play for the party urged the crowd. “Keep the faith.”

After Fox News called the presidency for Obama, the crowd, once in the hundreds, dwindled to just a few dozen. GOP officials largely stayed out of sight.

“The Romney campaign squandered this race this summer by not defining Romney while Obama pummeled him,” said former Republican Party Chairman Dick Wadhams. “Romney in the Denver debate got him back in the game, but not enough.”

Republican voters have about a 2 percentage-point advantage over Democrats in the state, and unaffiliated voters make up roughly a third. To win the state, Obama needed to turn out big numbers of Democrats, and appeal to enough unaffiliateds to make up the difference. And he did.

The president matched his 2008 success in turning out Democratic voters in places like Denver County, where he won 3-to-1, kept his losses to a minimum in Republican strongholds such as El Paso County, and fared better in some small, rural areas than four years ago.

Additionally, he won the state’s two most critical swing areas — Jefferson and Arapahoe counties — by 4 to 6 percentage points.

Overall in Colorado, Obama had 50 percent of the vote to Romney’s 48 percent with 1.9 million votes counted late Tuesday night.

Colorado State University political scientist Kyle Saunders said Romney did too little to reach out to women and Latino voters.

Though the campaign held rallies seeking to court those constituencies, it never crafted policies that appealed to them. And Saunders pointed to Romney’s comments during the second presidential debate when he said he relied on “binders full of women” to find qualified women to work in his administration as governor of Massachusetts as an example showing the campaign was “a little bit tone deaf on women’s issues.”

As a consequence, polls heading into Election Day showed Romney losing significantly among women and Latinos.

Jill Hanauer, the president of Project New America, a Denver-based Democratic research firm, said women were worried about Romney’s stances on women’s health care and, particularly Planned Parenthood.

“It’s not just about abortion,” she said. “It’s about health care and contraception.”

A survey of 1,029 Colorado voters who cast ballots between Oct. 29 and Nov. 4 showed Romney had an 11-point lead over Obama with white voters and a seven-point lead with those making at least $100,000 per year. But Obama led among Latinos and those making under $50,000. Although many polls nationally predicted a significant gender gap, Colorado exit polls showed women and men split equally. As expected, those surveyed said the economy was the most important issue facing the country, followed by the federal budget deficit and health care, according to the poll by Edison Research for The Denver Post.

Just days from the election, a Denver Post poll showed Romney trailing Obama by 2 percentage points — within the poll’s margin-of-error.

Obama’s Colorado team was banking on freshly registered voters in this state.

Democrats have a major advantage among the voters registered from July to October. Just 15 percent are white men older than 35, who lean Republican. The rest of new voters were women, under 35, African-American or Latino.

Obama’s Colorado campaign worked hard on messaging to suburban Republican and independent women, hitting hard on health care reform legislation that includes free coverage for mammograms and contraception. The campaign also heavily criticized Romney’s position on abortion.

Obama campaign manager Jim Messina called the 2012 get-out-the-vote strategy among the most sophisticated ever employed in politics — even calling the highly touted 2008 machine “prehistoric.”

Every Obama canvasser carried around smart phones packed with voter information, including how many times voters had been contacted by a volunteer and whether they had voted before.

Volunteers even had information from Facebook and paired “friends” with already-voted lists across the country, sending people individual messages to tell their Facebook friends to vote if they “like” Obama.

Obama volunteers had more than 5,000 “staging locations” — mostly in houses and basements and garages — in battleground states, including Colorado.

Volunteers worked almost 700,000 shifts in the past four days.

Even Republicans, who worked to mimic the Obama strategy four years ago, admitted they had to work to catch up. James Garcia, the head of Romney’s campaign in Colorado, said volunteers made twice as many phone calls and knocked on three times as many doors as in 2012. All told, the campaign made more than 2 million voter contacts since late September.

“We have never seen anything like it in Colorado on the Republican side of things,” said Rep. Cory Gardner, R-Yuma, who campaigned tirelessly for Romney.

“We knew this was going to be a tough fight,” said Gardner, who was re-elected Tuesday. “It is extremely difficult to beat an incumbent president.”

Gardner said House Republicans are willing to work with Obama but said they won’t compromise their principles and hurt “job-creators.” He said the tone of Obama’s campaign was not that of somebody who wants to work together.

“He didn’t win by bringing people together,” Gardner said. “He won by splintering the nation.”

Jennifer Brown: 303-954-1593, jenbrown@denverpost.com or twitter.com/jbrowndpost

Staff writers Jennifer Brown and Karen Crummy contributed to this report.