CONCORD, N.H. (AP) – Republican Sen. John McCain grabbed an early lead over former Massachusetts Gov. Mitt Romney in New Hampshire’s first-in-the-nation primary Tuesday night as he sought to climb back into contention for the presidential nomination. Sen. Barack Obama dueled with Hillary Rodham Clinton in the Democratic contest.

The economy and the war in Iraq were the top issues in both party primaries, according to interviews with voters leaving their polling places after casting ballots in the most wide-open presidential race in at least a half-century.

The first fragmentary returns showed McCain with an advantage over Romney in a race neither man could afford to lose. Former Arkansas Gov. Mike Huckabee, who won last week’s Iowa caucuses, was running third.

Obama vied with Clinton on the Democratic side, with former North Carolina Sen. John Edwards trailing.

Even before the votes were counted, Clinton’s campaign appeared to be bracing for a second straight defeat at the hands of Obama.

Officials said her aides were considering whether to effectively concede the next two contests – caucuses in Nevada on Jan. 19 and a South Carolina primary a week later – and instead try to regroup in time for a 22-state round of contests on Feb. 5.

These officials also said a campaign shake-up was in the works, with longtime Clinton confidante Maggie Williams poised to come aboard to help sharpen the former first lady’s message. Other personnel additions are expected, according to these officials, who spoke on condition of anonymity while discussing strategy.

Obama, who won the leadoff Iowa caucuses last week, looked for an endorsement from the powerful Culinary Workers union in Nevada in the days ahead. South Carolina’s Democratic electorate is heavily black and likely to go for the most viable black presidential candidate in history.

The Republican race turns next to Michigan, where McCain and Romney already are advertising on television, and where both men planned appearances on Wednesday.

By custom, the first handful of New Hampshire votes was cast, at midnight, in Dixville Notch in the far northern tip of the state.

By tradition, the first primary held the power to propel winners into the rush of primaries that follow – and to send the also-rans home for good.

And by registration, New Hampshire’s balance of power rested with its independent voters, more than 40 percent of the electorate, neither reliably Democratic nor Republican, with the power to settle either race, or both.

McCain, an Arizona senator, in particular, appealed for their support in the run-up to the primary. He battled Romney, the former governor of next-door Massachusetts, and to a lesser extent Mike Huckabee, the former Arkansas governor who won last week’s Iowa caucuses.

According to preliminary results of a survey of voters as they left their polling places, more independents cast ballots in the Democratic race than in the Republican contest. They accounted for four of every 10 Democratic votes and about a third of Republican ballots. The survey was conducted for The Associated Press and the television networks.

“It has all the earmarks of a landslide with the Dixville Notch vote,” an upbeat McCain quipped – he got four votes there to Romney’s two and one for former New York Mayor Rudy Giuliani – as his campaign bus headed to a polling place in Nashua. The crowd of supporters was so big, that voters complained and a poll worker pleaded with McCain to leave. Seconds later, the bus pulled away.

Former Tennessee Sen. Fred Thompson, Texas Rep. Ron Paul and California Rep. Duncan Hunter completed the Republican field.

Obama, too, hoped independent voters would come his way, as they did last week in Iowa, where he won the first test of the campaign. Clinton, the New York senator and former first lady, ran third in Iowa. Former Sen. John Edwards of North Carolina was second.

Obama drew huge crowds as he swept into New Hampshire, and as the front-runner drew plenty of criticism from Clinton and her husband. Asked if he expected more, Obama said, “Oh, I don’t think it will be just in the next few days. I think it’ll be, you know, until I’m the nominee or until I quit.” He said he understood their frustration.

Clinton, for her part, retooled her appeal to voters on the run. She lessened her emphasis on experience, and sought instead to raise questions about Obama’s ability to bring about the change he promised.

Win or lose, she said she was in the race to stay – never mind Edwards’ suggestion that the voters of Iowa had told her that her presence was no longer needed.

There was no letup in the television ad wars.

TNS Media Intelligence, a firm that tracks political advertising, said Clinton spent $5.4 million to reach New Hampshire voters, and Obama spent $5 million. The total for Edwards was $1.7 million, reflecting a smaller campaign treasury. New Mexico Gov. Bill Richardson, fourth candidate in the race, could afford about $500,000.

As happened in Iowa, Romney spent more than his rivals combined on television for the New Hampshire primary.

After losing Iowa, he could ill afford another defeat after basing his campaign strategy on victories in one or both states. Reflecting the stakes, he clashed in weekend debates with Huckabee over the Iraq war and with McCain over immigration as he tried to right his campaign.

On Tuesday, Romney put a positive face forward. “The Republicans will vote for me,” he said. “The independents will get behind me.”

McCain, too, was in need of a victory. Once the perceived front-runner, he suffered through a near-death political experience last year when his fundraising and support collapsed. He rallied, and by the final days of the New Hampshire race, held a celebration of sorts to mark his 100th town hall meeting in the state he won eight years ago.