Former NATO Gen. Wesley Clark's (search) campaign is gaining ground in the latest New Hampshire poll and Howard Dean (search) is slipping among Democratic supporters, according to the latest poll out Wednesday.

The Granite State's primary takes place on Jan. 27. Recent poll numbers show that Dean, the former Vermont governor, remains on top there, but new developments have emerged in the battle for second place. Whereas Massachusetts Sen. John Kerry (search) had been in the lead for second and was once a favorite to win that state, Clark has surpassed him for that position, according to American Research Group polls.

The polls show Clark steadily gaining ground. One taken Jan. 5-7 shows Dean with 35 percent of the vote, Clark with 18 percent and Kerry with 12 percent. One taken Jan. 4-6 gave Dean 36 percent of the vote, Clark 16 percent and Kerry 13 percent. In that poll, Sen. Joe Lieberman, D-Conn., got 7 percent, Rep. Dick Gephardt, D-Mo., got 6 percent and Sen. John Edwards, D-N.C., got 3 percent.

Clark's strength, according to the poll, remains among men age 45 and older. He also has a new television ad running in New Hampshire that gained very favorable playback from women.

If the trend toward Clark continues and he is able to improve among women age 45 and older, he will be alone in second place, according to American Research Group.

"The rest of the country really starts to pay attention when New Hampshire has its primary," political analyst Mary Ann Marsh told Fox News.

"If Clark comes in a strong second to Dean, if Dean maintains the lead he has — which is substantial — then [Clark] can lead himself nationally, which will give people a choice" for the Democratic nominee.

A Dec. 18 New Hampshire poll, conducted by ARG and released Dec. 18, showed that Dean led then with 45 percent of the Democratic vote, Kerry had 20 percent and Clark was tied with Lieberman for third.

A new national CNN/Gallup/USA Today poll released Wednesday also shows Dean's lead for the Democratic nomination narrowing. Twenty-four percent of registered Democrats and Democratic-leaning voters said they would choose him, while Clark came in second with 20 percent.

"Wesley Clark is the only one of the top-tier candidates … who is not part of the Washington establishment," GOP strategist Rick Reed told Fox News, "so it remains to be seen how precipitous this fall of Dean's is, whether it continues or not, and who will be the chief beneficiary."

The Gallup poll of 465 Democrats and those who lean Democratic had a margin of sampling error of plus or minus 5 percentage points, meaning Dean and Clark are essentially tied for the lead nationally. The poll was taken January 2-5.

In that same poll three weeks ago, Dean received 27 percent, while Clark and Lieberman were tied for second place with 12 percent each.

In recent weeks, Dean rivals have increased their criticism of his controversial statements, his record as governor of Vermont, and his feisty temperament.

"I think what's happened here, to some extent, is that the combined, collective attacks by other Democrats on Howard Dean are beginning to take their toll," Reed said. "Democrats are now looking at each other saying, 'oops, is this really the guy we want to run against President Bush?'"

The Gallup poll also shows that Bush had a substantial lead in a hypothetical matchup, outpolling Dean by a margin of 59 percent to 37 percent among likely voters. Bush also led, 55 percent to 38 percent, when likely voters were asked to choose between Bush and the generic "Democratic Party's candidate for president."

While the change in the national poll suggests Clark is gaining ground, the primary battle is being fought state by state. First up is Iowa on Jan. 19, where Clark is not competing, and then New Hampshire on Jan. 27, where polls indicate Clark is battling Kerry for second place.

In the national Gallup poll, Kerry was at 11 percent and Lieberman was at 10 percent. Other candidates were in single digits.

In the poll, Bush led Dean by 22 points, 59 percent to 37 percent. That's about the same advantage Bush had over Dean in mid-December in the poll.

In other news, former Vice President Al Gore will be campaigning in Iowa this weekend for Dean. Gore surprised most of the Democratic establishment recently when he announced his support for the doctor-turned-presidential hopeful.

Dean also on Tuesday gained the endorsement of former New Jersey senator and presidential hopeful Bill Bradley (search).

Fox News' Steve Brown and The Associated Press contributed to this report.