Dec. 11, 2007  -- The interaction of religion and politics is helping to roil the Republican presidential race, with Mike Huckabee and Mitt Romney gaining ground, while support for Rudy Giuliani, down especially among conservatives and highly engaged voters, has slipped to its lowest level of the year.

With a rally among evangelical Protestants, Huckabee's advanced sharply in this national ABC News/Washington Post poll, while Romney's made some progress allaying concerns about his Mormon religion. Along with Giuliani's diminished lead, his one-time chief competitors, John McCain and Fred Thompson, are near their own lows.

The upheaval reshapes the possibilities in the Republican contest, reflecting an electorate whose core groups have been uneasy with Giuliani and McCain, and uninspired by Thompson. Among Republicans and Republican-leaning independents, who say they're certain to vote, 25 percent in this poll support Giuliani, 19 percent Huckabee, 17 percent Romney, 14 percent Thompson and 12 percent McCain.

Huckabee's support has doubled from last month, while Giuliani's lost nine points. And while Giuliani retains a lead, it's nothing like his glory days early this year -- 53 percent in an ABC/Post poll last February, 30 points ahead of then-No. 2 McCain, with more modest double-digit leads subsequently.

Giuliani has dropped to 19 percent support among conservatives, a core Republican group uneasy with his backing of legal abortion and gay civil unions. He's down most sharply, by 20 points, among Republicans who are following the race very closely; they've shifted to Huckabee and Romney. And after two weeks on the defensive, Giuliani has lost considerable strength among his existing supporters: Just 28 percent of them now "strongly" favor him, down from 45 percent a month ago.

ISSUES: There's also a growing issue in the 2008 campaign, namely, the economy, which for the first time has surpassed the war in Iraq among the top two issues cited by likely voters. Among all Americans, 44 percent now say the economy's one of the top issues in their vote for president, up 15 points from last month; 37 percent name Iraq, down eight.

Just 28 percent, moreover, say the economy's in good shape, the lowest number since early 2003. Economic discontent can be a powerful political force, particularly if it finds a focus for blame.

DEMOCRATS: Unlike the Republican contest, this poll finds no upheaval in national preferences in the Democratic race, where, again among likely voters, Hillary Clinton leads Barack Obama by more than 2-1, 53-23 percent, with John Edwards at 10 percent, all essentially the same as last month.

This poll was conducted Thursday to Sunday, including interviews through the weekend when television personality Oprah Winfrey campaigned for Obama in Iowa, South Carolina and New Hampshire. It found no bump in support for Obama in Saturday and Sunday interviews; indeed, Democrats and Democratic-leaning independents are as likely to say Winfrey's endorsement makes them less likely to support Obama as more likely. Eighty-two percent say it makes no difference in their vote.

In a related result, just 5 percent of Americans overall say they put a great amount of weight on endorsements by entertainment figures or other celebrities. Vastly more rely heavily on the candidates' positions on the issues (65 percent), personal qualities (58 percent) and professional abilities (54 percent). Religion and spouses also are well back in importance, albeit ahead of celebrity endorsements.

BUSH/IRAQ: Then there's President Bush, inching closer to Harry Truman's record as the postwar president to linger longest without majority public support. Just 33 percent approve of Bush's job performance, matching his career low. It's been less than a majority for 35 months straight; the record was Truman's 38 months, from 1949-1952.

Bush's approval rating, depressed by the unpopular war in Iraq, has stayed remarkably flat, 33 to 36 percent in 10 ABC/Post polls the past year. In terms of intensity, strong disapprovers continue to outnumber strong approvers by a 3-1 margin.

Given reduced violence in Iraq, some views of the war have shifted, but not enough to change bottom-line attitudes. Forty-one percent believe the United States is making significant progress in Iraq, up from a low of 31 percent a year ago. But still, 61 percent say the war was not worth fighting; its strong opponents outnumber its strong supporters by 2-1 and 65 percent continue to disapprove of how Bush is handling it. He hasn't seen majority approval for handling the war since January 2004, nearly four years ago.

ELECTION: Bush's flat lines have likely helped make the 2008 race the focus of political attention, along with the fact that it's the first time since 1928 that neither the sitting president nor vice president sought his party's nomination. Seventy-two percent of Americans say they're following the contest closely, a new high in this cycle and far higher than the 45 percent number at this point in the last nonincumbert election, in 2000.

Democrats are more fired up. They're 10 points more apt than Republicans to "strongly" support a particular candidate. And given the president's long-running unpopularity, an overall decline in Republican allegiance continues. On average this year, just 25 percent of Americans have identified themselves as Republicans, down from a peak of 31 percent in 2003 and the lowest number since 1984 (when, it should be noted, Ronald Reagan was re-elected regardless, over a weak Democratic opponent).

But the sharper tone of the campaigns in recent weeks may be souring some voters. "Strong" support for candidates is down in both parties, now 44 percent, among leaned Democrats, down steadily from a peak of 63 percent in July; and 34 percent among Republicans, down from a high of 45 percent in September.

GOP CANDIDATES: In the Republican race, Giuliani has lost support particularly among men (down 14 points) and among independents, who lean toward the Republican Party (down 17 points, while both Huckabee and Romney are up by 10 points in this group).

Giuliani's also lost nine points among conservatives, and now is running about evenly with Huckabee and Romney in this group. That's Giuliani's lowest of the year among conservatives, and it compares with his 36 percent support from moderates and the few liberal Republicans. His challenge is that conservatives dominate; they account for six in 10 Republicans and Republican leaners.

Giuliani's greatest decline, as noted, has been among people who are following the race very closely, people perhaps more likely to be tuned in to recent questions about matters such as police security for his then-girlfriend when he was New York City mayor, and the identity of his security consulting firm's business clients.

Huckabee, governor of Arkansas and a Baptist minister, first caught on in Iowa, where an ABC/Post poll just before Thanksgiving found him challenging Romney, who's focused heavily on the state. Huckabee subsequently advanced in national polls, albeit not in New Hampshire, where he had just 9 percent support in an ABC/Post poll last week.

Huckabee's support in this national poll is up by 10 points among likely voters from last month. As in Iowa, he's advanced particularly among evangelical white Protestants, jumped from 13 percent support last month to a field-leading 29 percent support now. The main loss among evangelicals was McCain's, from 23 percent down to 12 percent.

It matters: Evangelicals account for 31 percent of all Republicans and Republican leaners, and 37 percent of likely Republican primary voters.

RELIGION: Romney, for his part, has gained seven points overall among registered voters, though less (a slight four points) among likely voters. Better is his progress on the issue of his religion, which he addressed in a speech last week: While 21 percent of leaned Republicans say they're less likely to vote for someone who's a Mormon, that's down from 30 percent in June and 36 percent a year ago.

These judgments matter; Romney has 20 percent support from Republicans who say Mormonism makes no difference in their choice, running second to Giuliani in this group versus almost no support among those less apt to back a Mormon candidate.

By contrast, this poll finds no net negative effect of a candidate's being a woman, an African-American, or a minister or other religious leader.

Romney may face further questions about his religion. Most Americans, 57 percent, believe they don't have a "good basic understanding" of it. And just 42 percent view Mormonism favorably overall; about as many, 39 percent, see it unfavorably, while 19 percent have no opinion. Romney's support is far higher, 28 percent versus 6 percent, among people who have a favorable opinion of his religion.

Religion is likely to continue to play a fascinating role in the race. Among all Americans just 27 percent say a political leader should rely on his or her religious beliefs in making policy decisions, a new low in ABC/Post polling and potentially a challenge for Huckabee or Romney in a general election contest.

At the same time, in his race for the nomination, Huckabee has 21 percent support among leaned Republicans who say a candidate should rely on his religious beliefs in making policy decisions. Among those who oppose reliance on religious belief in policy matters, Huckabee's support drops to 10 percent.

GOP ATTRIBUTES/ISSUES: Giuliani, whatever his problems, continues to prevail on two important attributes: He's easily seen as the most electable in November (with nearly a 3-1 lead over Romney, the No. 2 finisher on this attribute), and as the strongest leader (2-1 over McCain). Giuliani also has a scant five-point edge over McCain and Huckabee as the candidate who "best understands the problems of people like you."

But he's only even with McCain in terms of experience; there's virtually a four-way tie among these four top candidates on who's the most honest and trustworthy, and all five top candidates, also including Thompson, are in the mix on who best represents the core values of the Republican Party.

On issues, Giuliani leads in trust to handle terrorism, a cornerstone of his campaign, and has an advantage on economic issues, potentially useful as this concern grows. But he and McCain are about even in trust to handle Iraq and immigration, and he, Romney and Huckabee, are about matched on "social issues, such as abortion and gay civil unions."

DEMOCRATS: This poll finds more clear-cut preferences on the Democratic side, where the contest looks very much now as it has since September. Clinton's overall lead is buttressed by very large advantages as the best experienced candidate, the strongest leader and the most electable in a general election. She also has a significant lead on empathy, wider than when that attribute was last tested in June.

Clinton has a much narrower eight-point advantage on honesty and trustworthiness, long a weaker suit for her. And Obama runs evenly with her in one last attribute, being the "most inspiring" candidate.

On issues, again, Clinton prevails with very large leads in trust to handle health care, the economy, Iraq and terrorism alike.

While Clinton leads among both sexes, she again has a bigger advantage among women than men. Indeed, she leads in this poll across demographic groups, including a 13-point advantage among African-Americans, who've been oversampled in ABC/Post polls all year for more reliable analysis.

ISSUES: There is, again, a significant difference between leaned Democrats and leaned Republicans when it comes to the top issues in their vote; Democrats converge around three issues -- the economy, Iraq and health care -- while Republicans bring in terrorism and immigration as well.

But among both groups there's been a drop in mentions of Iraq as the top issue, and increases in concern about the economy, a looming wildcard in the 2008 election.

METHODOLOGY: This ABC News/Washington Post poll was conducted by telephone Dec. 6-9, 2007, among a random national sample of 1,136 adults, including an oversample of African-Americans for a total of 205 black respondents (weighted back to their correct share of the national population). The results have a three-point error margin for the full sample, four points for the sample of 610 Democrats and Democratic-leaning independents, five points for the sample of 409 Republicans and Republican-leaning independents, 4.5 points for the sample of 429 likely Democratic primary voters and 5.5 points for the sample of 293 likely Republican primary voters. Sampling, data collection and tabulation by TNS of Horsham, Pa.