Congressional Republicans and President Bush have seized upon the Terri Schiavo case with such fervor that they may find themselves out in front of an American public that is divided over right-to-die issues and deeply leery of government intrusion into family affairs, according to analysts and polls.

Dominating a debate that many Democrats seem eager to avoid, conservative lawmakers and the White House have taken extraordinary steps to allow a federal judge to override the decisions of Florida courts to remove the brain-damaged woman's feeding tube. Antiabortion activists, a key GOP constituency, have cheered the moves, which included Bush rushing back to Washington to sign the bill in the dead of night after a rare Palm Sunday congressional session.

In another sign of the priority that the GOP has placed on the Schiavo matter, they have let it trump their traditional calls for a limited federal judiciary and respecting the "sanctity of marriage."

Bush said yesterday that his decision to fly back from his Texas ranch to the White House to sign the legislation gave Schiavo's parents "another opportunity to save their daughter's life." Speaking in Tucson before an event promoting his plan to restructure Social Security, he said: "This is a complex case with serious issues. But in extraordinary circumstances like this, it is wise to err on the side of life."

Republicans in Congress and administration officials say their actions are principled and courageous. Whatever the motives, dramatic actions on such a high-profile case will have repercussions in next year's congressional elections, campaign strategists say.

Polls and analyses suggest that Republicans could find themselves out of step with many Americans, especially if Democrats find a more unified voice on the subject. An ABC News poll released yesterday concluded that "Americans broadly and strongly disapprove of federal intervention in the Terri Schiavo case, with sizable majorities saying Congress is overstepping its bounds for political gain."

By 63 to 28 percent, Americans support the removal of Schiavo's feeding tube, which her husband says would be her wish. Seventy percent of the respondents said it was inappropriate for Congress to get involved as it has. And 67 percent said they believe that elected officials trying to keep Schiavo alive are doing so mainly for political reasons.

The poll suggests that Democrats have an opportunity to speak for a significant portion of Americans who feel the GOP is overreaching. But whereas Democratic lawmakers continue to attack the administration's Social Security plans -- which polls also show to be unpopular -- they seem far more reticent on the Schiavo case. None of the Senate's 44 Democrats tried to delay the legislation that some of their House colleagues denounced as dangerous and unconstitutional.

"The Republicans may be setting themselves up for problems" in the 2006 elections, said Democratic pollster Doug Schoen, "but I don't think we're there yet." Democrats are divided over how to respond to the emotional right-to-die issue, he said, and as long as there is not a "Democratic worldview," strongly committed conservatives will control the debate.

The actions by Bush and the GOP-controlled Congress heartened many conservative activists. "It was necessary and very touching to see he was willing to go to those lengths to help this abused woman," said Wendy Wright, senior policy director for Concerned Women for America, a conservative advocacy group. "This is an issue of right and wrong, and what President Bush has done is come down on the side of right, which is to protect life."

Some Democrats quietly grumbled that Bush's dramatic return to Washington was orchestrated in part to curry favor with such conservatives. An unsigned memo circulated among GOP senators calling the Schiavo case "a great political issue" bolstered that view.

Rather than incurring the cost of flying back to Washington on Air Force One -- pegged in 1999 at $34,000 an hour -- Bush could have signed the bill in Texas a few hours later without significantly endangering Schiavo's life, critics said. Not only had doctors estimated that she could live for up to two weeks without the feeding tube, but a federal judge was not expected to hear the case until today.

"Obviously, Bush could have signed the bill in Texas," said Dan Bartlett, a senior counselor to Bush. But, he added, despite the estimates of how long Schiavo could live without her feeding tube, "it would be very hard for anyone to live with themselves" if Schiavo died because of a delay in the signing of the bill into law.

Some Democrats liken the Schiavo situation to debates over gun control, in which a fiercely committed minority -- led in part by the National Rifle Association -- has thwarted legislation supported for years by most Americans.

"Our folks are nervous about this," said a high-ranking House Democratic aide, one of several who would speak only on background because of the topic's sensitivity. Democrats are aware of the polls, he said, but also wary of the intensity and determination of the conservative groups -- many of them steeped in the politics of abortion -- that are demanding that Schiavo be kept alive.

Democrats may be misreading the public's mood, however. "The intensity of public sentiment is . . . on the side of Schiavo's husband," the ABC poll concluded, with more Americans strongly supporting the feeding tube's removal than strongly opposing it.

Rep. Barney Frank (D-Mass.), a liberal who spoke strongly against the legislation Sunday night, said Democrats should cite it in next year's elections as an example of congressional Republicans having too much power driven by hard-right ideology. "The American people have a distrust of excessive zeal, and some of the Republican leaders' determination to impose their religious views borders on fanaticism," he said. "They're playing God."

Democratic senators -- who represent larger, more diverse constituencies than do House members -- have eschewed such hard-hitting comments. Jim Manley, spokesman for Senate Minority Leader Harry M. Reid (Nev.), noted that Democrats including Sens. Ron Wyden (Ore.) and Carl M. Levin (Mich.) spoke publicly against the legislation but saw no point in trying to postpone it.

"It was clear this bill had majority support, and there was no point in delaying a vote," Manley said.

The new law appears to conflict with a Texas law Bush signed as governor, according to lawyers familiar with the legislation. The 1999 Advance Directives Act in Texas allows a patient's surrogate to make end-of-life decisions and spells out how to proceed if a health provider disagrees with a decision to maintain or halt life-sustaining treatment.

Thomas Mayo, an associate law professor at Southern Methodist University who helped draft the Texas law, told the Associated Press that if the Schiavo case had happened in Texas, the husband would have been her surrogate decision maker. Because both he and her doctors were in agreement, life support would have been discontinued, he said.

White House spokesman Scott McClellan told reporters that the law Bush signed in 1999 "is consistent with his views. . . . [It] actually provided new protections for patients."

Fletcher reported from Tucson. Staff writer Mike Allen contributed to this report.