Clinton has clear leads in New Hampshire and South Carolina, building on her ownership of the health-care issue and her broad but more fragile trust among Democrats on Iraq, the survey showed Monday. Yet she could stumble in Iowa, whose Jan. 3 caucuses will be the first voting and where she is in a scramble with Barack Obama, trailed closely by John Edwards.

An extensive poll in the three states by The Associated Press and the nonpartisan Pew Research Center finds Democrats enthusiastic about their overall presidential field. Most rate it strongly, and they spiritedly back the contenders they prefer.

The poll shows Clinton's advantages in the early contests stretch beyond the top issues. The New York senator has amassed strong support among crucial groups including female, older, less-educated and lower-income Democrats — significant because women and older voters in particular have dominated these primaries and caucuses in the past. In Iowa though, she has only a modest lead over Obama among women.

"She knows how to deal with the opposition, she can get national health care passed and stop the war in Iraq," said Steven Arcone, 63, a geophysicist and Clinton supporter from West Lebanon, N.H.

The AP-Pew poll shows:

—Clinton essentially tied with Obama in Iowa, 31 percent to 26 percent, with Edwards at 19 percent and New Mexico Gov. Bill Richardson at 10 percent.

—In New Hampshire Clinton 38 percent, Obama 19 percent, Edwards 15 percent, Richardson 10 percent.

—In South Carolina Clinton 45 percent, Obama 31 percent, Edwards 10 percent.

Obama and Edwards haven't taken title to any issues with party voters in the three states, the poll shows, though Obama is close to Clinton on immigration and job creation. Unfortunately for the Illinois senator, neither concern is more than a blip for Democrats, with only one in 20 listing them atop the agenda.

The two men have only scattered strength among Democratic blocs, with Obama's strongest backing coming from Democratic-leaning independents, liberal, younger and better-educated voters. That is especially true in Iowa, which has helped vault him into contention there.

Edwards, the former North Carolina senator, has yet to lay claim to any critical group of Democrats in the three states.

Even among blacks who comprise about half of Democratic primary voters in South Carolina, Obama does no better than break even with Clinton. She offsets that by leading him by three-to-one among the state's whites. There are few black voters in Iowa or New Hampshire.

"We need somebody right now who can address" Iraq and health care, said J.W. Sanders Sr., 78, pastor of Bethel Baptist Church in Gaffney, S.C. "This isn't something I have against Obama. But I feel we must look now beyond gender as well as race."

Democrats in each state overwhelmingly call Clinton the Democrat with the best chance of winning the White House. Yet that doesn't carry the weight it did in 2003, when it helped Sen. John Kerry of Massachusetts win the nomination. Not even one in four says he would prefer an electable candidate to one with whom he agrees on the issues — more than 10 percentage points fewer than in 2003 in Iowa and New Hampshire, and about the same as said so then in South Carolina.

In all three early states, Democrats trust Clinton more than her rivals on Iraq, though by smaller numbers than she gets nationally from her party. Even so, she has small double-digit leads over Obama and Edwards in Iowa and New Hampshire when Democrats are asked which candidate would make the wisest decisions about the war, and is tied with Obama in South Carolina.

All top Democrats have said they want to end the war, though Clinton has drawn criticism for her 2002 vote supporting the use of force against Saddam Hussein and for saying she would continue combat operations against al-Qaida in Iraq. Strong majorities of Democrats want to bring the troops home.

On health care, no rival approaches the support Clinton wins from party voters. The 41 percent in Iowa who say she would best improve the country's medical system is double the support for Obama and Edwards, and she boasts even wider leads in New Hampshire and Iowa.

Clinton and Edwards want universal health coverage, while Obama would expand coverage but not require people to buy insurance. In each state surveyed, eight in 10 Democrats favored government-guaranteed health insurance, even if it means higher taxes.

Iraq and health care are essentially tied in all three states as concerns Democrats most want presidential candidates to address, with each named by roughly one-third.

Despite Clinton's leads in New Hampshire and South Carolina and her front-runner status nationally, Iowa's often unpredictable caucuses threaten to trip her before she can fashion an unstoppable head of steam.

Clinton draws the support of nearly half of women in New Hampshire and South Carolina. Yet in Iowa, women split 34 percent for Clinton, 27 percent for Obama and 17 percent for Edwards.

"The things he grew up with, a single mom, working hard to get where he's gotten, I just get a good feeling about him," Nola Olson, 35, teacher's aide in Adel, Iowa, said of her candidate, Obama.

He and Edwards have more support than Clinton as a second choice in Iowa — which could be important on caucus night, when candidates with weak support are eliminated. Eighteen percent of Iowa Democrats rule out voting for her — far more than her two chief opponents and approached only by the 12 percent who shun Rep. Dennis Kucinich of Ohio.

Mark Penn, Clinton's chief strategist, attributes her weaker showing in Iowa to a late start there and her husband Bill's bypassing the state in his two successful presidential campaigns. Obama pollster Cornell Belcher says Iowa is where the candidate has been most active.