MERRIMACK, N.H. - Riding an Iowa crest, Illinois Sen. Barack Obama has caught New York Sen. Hillary Rodham Clinton in the Democratic race for the New Hampshire primary, while Arizona Sen. John McCain maintains a solid lead in the Republican contest, according to a new McClatchy-MSNBC poll.

Thanks to an apparent surge of support the night after he won the Iowa caucuses, Obama had the support of 33 percent of likely Democratic primary voters. Clinton came in at 31 percent.

Given the poll's margin of error, 5 percentage points, the two are about even. But that still marks a gain for Obama, who has trailed Clinton in New Hampshire for months.

Former Sen. John Edwards of North Carolina came in at 17 percent.

On the Republican side, McCain led the field with 32 percent over former Massachusetts Gov. Mitt Romney's 24 percent. There, it was McCain who got a bounce, not Iowa winner Mike Huckabee, the former governor of Arkansas who still trails in third place at 12 percent and appeared to get no immediate traction from Iowa.

The new poll is hardly a prediction. If anything, it revealed an electorate in New Hampshire still very much up for grabs.

Its three nights of interviews straddled the Iowa results -- before, during and after -- and could have recorded merely a blip for Obama or the start of a wave. It also came before potentially pivotal debates in New Hampshire on Saturday night and today that could swing the Tuesday vote in any direction.

Underscoring the volatility: Three of 10 likely voters in each party said they could still change their minds; nearly one of 10 New Hampshire independents said they still hadn't decided in which primary to vote.

But the poll may have picked up the beginning of an Obama rally. Obama trailed Clinton, with 27 percent to her 30 percent, the first two nights of the polling, then surged ahead, with 39 percent to Clinton's 32 percent, Friday night -- the day after Iowa. The nightly sample was smaller than the overall sample of 400, however, and subject to a greater margin of error.

The independent vote

Independents are a key factor in New Hampshire, where they can vote in either primary.

"New Hampshire independents clearly favor Obama on the Democratic side and McCain on the Republican side," said Brad Coker, managing partner for Mason-Dixon Polling and Research, which conducted the poll Wednesday through Friday.

"They are, in fact, providing the margins for the two nominal leaders," he added, noting that registered Democrats actually break for Clinton and registered Republicans split almost evenly between McCain and Romney.

Overall, Obama had a solid lead among young voters, independents, those looking for change, and those who rank Iraq or the economy their top concern.

His weakness remained older voters, who preferred Clinton, and those who want experience, who favored either Clinton or New Mexico Gov. Bill Richardson.

On the Republican side, the poll suggests that after Iowa, McCain gained in New Hampshire as Romney and Huckabee failed to advance.

In surveys conducted the night after Iowa, McCain, who did not compete in the caucuses, gained 6 points.

He owes his overall lead to his solid appeal to independents, and to men, those looking for experience and leadership, and those who rank national security, the economy or taxes their top concerns.

Romney lost his longtime lead in Iowa and finished second there despite spending the most money. He has an edge among women, those looking for someone who shares their values and view of the issues, and those who rank illegal immigration their top issue.