DES MOINES, Iowa (AP) ― Mitt Romney edged Rick Santorum by eight votes to win Iowa’s Republican presidential caucuses in the opening contest in the campaign to pick a challenger to President Barack Obama, the state party chairman said.

Appearing early Wednesday hours after the caucuses had ended, Iowa Republican chairman Matt Strawn said Romney had 30,015 votes, to 30,007 for Santorum, whose campaign only recently gained momentum.

The narrow margin, out of more than 122,000 ballots cast, was a fitting conclusion to a race as jumbled as any since Iowa gained the lead-off position in presidential campaigns four decades ago.

Texas congressman Ron Paul ran a strong third in the caucuses ― evening meetings held at 809 locations across the midwestern state Tuesday.

The two rivals many Republicans saw as having the best backgrounds to challenge Romney ― former House Speaker Newt Gingrich and Texas Gov. Rick Perry ― were far behind the leaders in fourth and fifth places, respectively. Gingrich vowed to stay in the race, but Perry told supporters he would return home to Texas to reassess his candidacy.

Minnesota congresswoman Michele Bachmann was a distant sixth, and her campaign appeared in disarray. She told reporters she would carry on ― less than an hour after her campaign manager raised doubts in an Associated Press interview about whether she would stay in the race.

Both Perry and Bachmann had been in the top tier of candidates earlier in the race.

The seventh candidate, former Utah Gov. Jon Huntsman, who served as Obama’s ambassador to China, did not campaign in Iowa.

The results were a respectable showing for Romney. Iowa, with its core of evangelical voters, was not considered a natural stronghold for the former governor of the liberal state of Massachusetts. He clearly remains the candidate to beat for the party’s nomination going into next Tuesday’s New Hampshire primary, where he is the clear favorite.

“On to New Hampshire!” Romney told supporters shortly before midnight before the final results were announced. “We’ve got some work ahead.”

Still, Iowa reflects Romney’s inability to build support beyond the 25 percent level he has held for months in national polls ― even though he is generally considered the most formidable challenger to Obama in the seven-candidate field.

But the results also show no obvious alternative to Romney. Despite their strong performances Tuesday, Santorum and Paul remain longshots for the nomination.

Santorum, a former Pennsylvania senator who for months languished at the bottom of Republican polls, may be hard-pressed to repeat his Iowa performance, where his solid conservative stances on social issues like abortion and gay marriage resonated with Republican voters. It’s not clear whether the message will work as well in states where the economy is a bigger issue or if he can come up with the funds or organization to sustain a national campaign.

Also, he has yet to face the intense scrutiny that has caused other conservative challengers to Romney to wither as soon as they climbed to the top of polls.

Paul’s advocacy of small-government, libertarian values has won him a devoted core of supporters, including in the important tea party movement which fueled the Republican wave victory in the 2010 congressional elections. But his anti-interventionist foreign policy and criticism of aid to Israel puts him at odds with much of the party.

It’s not clear as the Republican field narrows whether the party will rally behind Romney as the inevitable nominee or coalesce behind an anti-Romney conservative alternative such as Santorum.

Before cheering backers, Santorum vowed to press ahead with the same conservative themes that put him in contention to win Iowa’s caucuses.

“Thank you so much, Iowa, for standing up and not compromising, by standing up and being bold,” Santorum said. “You have taken the first step toward taking back this country.”

Returns from all 1,774 precincts showed Romney with 24.55 percent support and Santorum with 24.54 percent. Paul drew 21.5 percent of the votes. Romney had 30,015 votes, Santorum 30,007 and Paul 26,219.

Gingrich had 13 percent, followed by Perry at 10 percent and Bachmann with 5 percent.

The results are non-binding when it comes to picking delegates to the Republican convention in late August in Tampa, Florida, when the nominee will be formally selected. But an Associated Press analysis showed Romney would win 13 and Santorum 12, if there were no changes in their support as the campaign wears on.

No matter how close the final results in Iowa, there were no plans for a recount.

Iowa has an uneven record when it comes to predicting national winners. It sent Obama on his way in 2008, but eventual Republican nominee John McCain finished a distant fourth here to former Arkansas Gov. Mike Huckabee. The 100,000 or so voters in the Republican caucuses are disproportionately white and more conservative than the overall American electorate.

Unlike in a primary, in which voting occurs over hours, the Iowa caucuses were meetings held in schools, churches and other locations where Republicans gathered for an evening of politics. Each presidential candidate was entitled to have a supporter deliver a speech on his or her behalf before straw ballots were taken.

Romney, who finished second in Iowa in 2008 despite a costly effort, initially campaigned cautiously this time around. But that changed in the race’s final days as he pursued a first-place finish, running as a conservative businessman with the skills to fix the economy. This time, Romney drew a smaller share of the vote than the 25.2 percent he received in 2008.

His rivals argued that Romney wasn’t nearly conservative enough on the economy and social issues such as abortion and gay rights.

Democrats watched carefully in a state that has swung between the two parties in recent presidential elections.

Obama was unopposed for his party’s nomination. Even so, his re-election campaign set up eight offices across Iowa, made hundreds of thousands of calls to voters and arranged a video conference for the president with caucus night supporters.

“This time out is going to be in some ways more important than the first time,” Obama told Democrats across the state. “Change is never easy.”

The state’s leadoff spot has been a fixture for decades. Democrats moved the caucuses up to early January in 1972, and Republicans followed suit four years later.