By Jackie Calmes. New York Times.

WASHINGTON — For decades, Republicans have railed every four years against the Supreme Court and its perceived liberal activism to spur conservatives to elect presidents who will appoint like-minded justices. Now strategists in both parties are suggesting this could be the Democrats’ year to make the court a foil to mobilize voters.

The prospect arises both because of President Obama’s comments this week implicitly warning the court against striking down his signature domestic achievement, the expanded health insurance law, and because of recent court rulings, chiefly the Citizens United campaign finance decision, and looming cases on immigration and affirmative action that incite passions on the left.

“Historically, the court has been a rallying point for the Republican base, and it is now much easier to imagine that it will be a rallying point with the Democratic base just as much if not more, especially if the court overturns the Affordable Care Act,” said Geoff Garin, a Democratic pollster who works with Priorities USA Action, a group supporting the president’s re-election but independent of his campaign.

“My guess,” Mr. Garin added, “is that more voters will think, ‘If they can do that, they can do just about anything — and that includes overturning Roe v. Wade’ ” — the landmark 1973 abortion rights decision.

Though the justices are not expected to rule on the 2010 health care law until June, the public reaction to the three days of arguments last week offered evidence of a potential Democratic backlash. In a poll for The Washington Post and the Pew Research Center for the People and the Press, 32 percent of Democrats said they had a less favorable opinion of the Supreme Court after the hearings, compared with 14 percent of Republicans.

“There’s evidence here of a negative reaction from Democrats,” said Michael Dimock, Pew’s associate director for research. The justices “didn’t even decide anything yet, and many people walked away from their hearings feeling more negative about the court. So you can imagine the reaction if they overturn the law.”

Officials at the White House and with the Obama campaign would not comment for the record, though several insisted there was no political strategy to run against the Supreme Court’s conservative majority — at least not unless the court invalidates the health care law. Aides said Mr. Obama, a former Harvard Law Review president and constitutional law instructor at the University of Chicago, had simply been answering the predictable questions about his reaction to the hearings.

And much as Democrats argued in past election seasons, some aides expressed skepticism about how effective the issue could be in the election, given the public’s poll-tested lack of interest in the court.

Republicans, by contrast, have made it an issue since Richard M. Nixon, running in 1968, denounced the Warren-era court for liberal rulings on social issues and criminal procedures, and made phrases like “judicial activism,” “legislating from the bench” and “strict constructionism” presidential-year perennials for conservatives.

The criticisms fit with the broader Republican message against crime, cultural permissiveness and the removal of Christian faith from public policy. In the Republicans’ current contest for the presidential nomination, Newt Gingrich courted conservatives by arguing for elected officials to ignore judicial decisions they oppose. Last week, Rick Santorum joined protesters of the health care law outside the Supreme Court.

“I don’t think there’s a single presidential campaign going back to 1968 upon which the result turned on the Supreme Court generally or a single Supreme Court case,” said Joel Benenson, an Obama pollster.

“To the extent it would be a motivating issue this year,” he added, “it would be for Democratic and independent voters around the Citizens United case.”

That decision, with five Republican-appointed justices forming the majority, overturned precedents and allowed corporations and individuals to give unlimited sums of money to support independent campaigns on behalf of political candidates — a freedom that has helped define the Republican presidential contest.

Mr. Garin said his polling and focus groups showed that Citizens United “is probably the best-known decision since Bush v. Gore” — the 5-to-4 ruling that decided the deadlocked 2000 presidential election for the Republican, George W. Bush.

What makes the Citizens United case resonate with Democrats and some independent voters, party strategists say, is its fit with many Americans’ sense that the political system, including the conservative court, favors corporate and special interests.

“The jurisprudential divide on the Supreme Court regarding high-profile legal issues now appears to map almost perfectly onto the political divide that exists in the larger nation,” said Justin Driver, a law professor at the University of Texas, who was a law clerk to Sandra Day O’Connor, a former Republican appointee, and Justice Stephen G. Breyer, a Democratic appointee. “I do think that this may be a year for the Supreme Court to play a prominent role in the election in a way that we have not seen in a long time, maybe ever.”

Increasingly, Professor Driver said, the court splits 5 to 4, with appointees of one party opposite those of the other. That was true of Monday’s ruling that local officials can strip-search anyone being jailed, no matter how minor the alleged offense and regardless of whether there is reason to suspect contraband.

In contrast, court decisions of past decades that most roiled conservatives often had lopsided majorities or even unanimous votes. Until recently, party affiliation had little bearing. For example, the dissenters in Bush v. Gore included two Republican appointees, while the author of Roe v. Wade was a Republican appointee and its chief dissenter a Democratic appointee.

Noah Feldman, a professor at Harvard Law School, said “the smart money” among legal scholars was on the court’s upholding the health care law. But if the law is overturned, he said, the court is certain to be a major issue in the presidential campaign.

Together with decisions like Citizens United, he said, “that would add up to a real pattern of conservative judicial activism, of a kind that will really be unprecedented since the New Deal.”

Mr. Obama made that argument on Tuesday to a convention of newspaper editors, seeking to clarify his much-criticized comment on Monday that it would be “unprecedented” for the court to strike down a law.

On Tuesday he said he had meant that the court had deferred to Congress on matters affecting interstate commerce — like health care — “at least since Lochner.” That referred to the judicial era before the New Deal, when pro-business courts routinely invalidated laws on minimum wages, child labor and business regulations.