Nominations to the Supreme Court have inspired many of the nasty, defining partisan battles of the last generation in Washington, creating a whole cottage industry of interest groups on both the left and the right.

President Obama's nomination of Sonia Sotomayor, however, has the potential to quiet the usual noise.

That's because Republicans will need to tread lightly in opposing the woman who would be the first Hispanic justice, lest they risk further alienating the nation's fastest-growing group of voters.

Republicans experienced a sharp drop in Latino support in 2008, after eight years of efforts led by former President George W. Bush to increase the party's appeal. Exit polls found that Obama captured 67 percent of the Hispanic vote, running 16 percentage points better than 2004 Democratic nominee John Kerry.

The GOP's image had suffered among Hispanics in part by conservatives' push for a crackdown on illegal immigration in debates during 2006 and 2007 over Bush's effort to provide a path to citizenship for undocumented workers.

"If the debate over Judge Sotomayor starts to get too negative, it could hurt the Republicans with Hispanics, and they still have an immigration debate looming," said Matt Barreto, a political scientist and pollster at the University of Washington. "They'll have to ask how important it is to block this judge, especially if she's likely to be confirmed anyway."

Eighty-one percent of Latino voters already approved of Obama's job performance in a Latino Decisions poll Barreto conducted with Pacific Market Research earlier this month.

"Republicans would be idiots for opposing her," Lionel Sosa, a GOP strategist who advised Bush on Hispanic outreach, told the Associated Press. ". . . It would be one more nail in the Republican image coffin."

Even Alberto R. Gonzalez, attorney general under Bush, called the nomination a "powerful message of hope and opportunity."

Last fall's shift among Hispanics was important because it was key to the strategic realignment of the Mountain West states, for the last 25 years a part of the GOP's geographic base.

Obama flipped Colorado from red to blue on the strength of a 73 percent share of the Latino vote, and captured Nevada with 76 percent of Latino voters and New Mexico with 69 percent. The Hispanic share of the electorate increased in all three states.

Conservative activists came out strongly against Sotomayor yesterday, denouncing her as an out-of-the-mainstream liberal who has demonstrated a willingness to legislate from the bench. They particularly seized on a clip from a Duke University forum that shows Sotomayor saying that circuit courts are "where policy is made," and past statements in which the judge said that her experiences as a Latina had affected her decisions.

"Judge Sotomayor is a liberal judicial activist of the first order who thinks her own personal political agenda is more important than the law as written," said Wendy Long, of the conservative Judicial Confirmation Network.

"She thinks that judges should dictate policy, and that one's sex, race, and ethnicity ought to affect the decisions one renders from the bench."

Citing a case in which Sotomayor ruled against a challenge by white firefighters to an affirmative-action policy in New Haven, Conn., radio talker Rush Limbaugh called her a "reverse racist."

Republican senators were considerably more measured.

"Senate Republicans will treat Judge Sotomayor fairly," Minority Leader Mitch McConnell of Kentucky said. "Our Democratic colleagues have often remarked that the Senate is not a 'rubber stamp.' Accordingly, we trust they will ensure there is adequate time to prepare for this nomination, and a full and fair opportunity to question the nominee and debate her qualifications."

Sen. Jeff Sessions (R., Ala.), the party's ranking member on the Judiciary Committee, promised a "fair and thorough examination" of the nominee's record.

Sen. Jim DeMint (R., S.C.), a leading conservative who said Sotomayor's writings raised questions about her commitment to judicial restraint, said he would "withhold judgment" until the hearings.

Heather Heidelbaugh, a Pittsburgh lawyer and Republican activist, said she believed it was possible to celebrate Sotomayor's historic status and also conduct a "proper examination" of her fitness to serve.

"I identify with her," Heidelbaugh said, adding that she was inspired by Sotomayor's fight against juvenile diabetes, the disease Heidelbaugh's daughter has.

At the same time, the Duke law school comments raise a concern, she said.

"I prefer a judge who calls the balls and strikes and leaves the policy to the legislative branch," Heidelbaugh said.