Former House Speaker Newt Gingrich on Wednesday called Supreme Court nominee Judge Sonia Sotomayor a “racist” for remarks she made in 2001, joining an emerging conservative line of attack and enflaming both sides of the battle as interest groups fundraise over her nomination.

Mr. Gingrich, in his Twitter feed to more than 344,400 followers, called on Judge Sotomayor to withdraw from consideration to the high court. He said her remarks citing ethnic background as a reason for making better legal decisions, if spoken by a white male, would be disqualifying.

“Imagine a judicial nominee said, ‘My experience as a white man makes me better than a Latina woman.’ New racism is no better than old racism,” Mr. Gingrich wrote on Twitter, which he uses regularly to discuss politics or promote his television appearances.

Mr. Gingrich followed his initial tweet a few minutes later with: “White man racist nominee would be forced to withdraw. Latina woman racist should also withdraw.” He gained more than 1,000 followers after the remarks.

The White House warned that Republicans should be “exceedingly careful” with such language, and even conservative groups cautioned that going after President Obama’s nominee with this line could be toxic to a party losing ground with Hispanic voters.

But conservative radio host Rush Limbaugh told his millions of listeners Wednesday they should charge ahead.

“If the GOP allows itself to be trapped in the false premise that it’s racist and sexist and must show the world that it isn’t, then the GOP is extinct,” Mr. Limbaugh said on his radio program Wednesday.

The widely cited comments Judge Sotomayor made at the University of California, Berkeley eight years ago are: “I would hope that a wise Latina woman with the richness of her experiences would more often than not reach a better conclusion than a white male who hasn’t lived that life.”

“Whether born from experience or inherent physiological or cultural differences, our gender and national origins may and will make a difference in our judging,” she said.

She went on to make broader points about diversity of experience as it relates to the law, but her comment has been fodder for critics of the impending nomination, and is likely to surface in the confirmation hearings that will take place in July.

Conservative groups say they must get involved to activate their base in time for the 2010 elections and demonstrate the ideological differences between the parties.

Carrie Lukas, vice president for policy and economics at the Independent Women’s Forum, said the opposition has a purpose: “To help educate voters that elections have consequences.”

“The idea that you pull back from a fight because someone is from a different ethnic group is part of the mistake Republicans made and how we got President Obama in the first place,” said Ron Robinson, president of Young America’s Foundation.

James L. Martin, president of the conservative 60 Plus Association, a seniors lobbying group, said conservatives are stuck in a tough spot because opposing the first potential Hispanic justice “means the lib media will portray us as anti-Hispanic and racist.”

White House press secretary Robert Gibbs dismissed the Gingrich remarks as coming from a “former lawmaker” and smacking of “partisan politics.”

“It is probably important for anybody involved in this debate to be exceedingly careful with the way in which they’ve decided to describe different aspects of this impending confirmation,” Mr. Gibbs said when asked about the remarks.

Mr. Gingrich’s tweets immediately rocketed around the blogosphere, generating hundreds of responses on Twitter and elsewhere within an hour. Some said they agreed, while many others blasted the former speaker.

A Daily Kos blogger took particular offense, when the Gingrich tweet came within a day of his self-described visit to the gas chambers at Auschwitz for a film project.

“Gingrich seems to be misreading his fingerometer, or he’s standing in an ill wind. Channeling Rush doesn’t help you, Newt,” wrote “bumblebums” on Twitter.

But “inkwellgallery” called Mr. Gingrich a “smart man” and urged users to follow the former speaker.

On Tuesday Mr. Limbaugh went as far as calling Judge Sotomayor a racist for the Berkeley comments, then added, “You might want to soften that and you might want to say a reverse racist.”

Senate Democrats jumped on the Limbaugh remarks, partially quoting the man they labeled “de facto party spokesman” in an e-mail aimed at rallying supporters to back Judge Sotomayor.

“With statements like that from Limbaugh, we can expect to have a fight on our hands,” Sen. Bob Menendez, chairman of the Democratic Senatorial Campaign Committee, wrote party members Wednesday.

Meanwhile, the ranking Republican on the Judiciary Committee, Sen. Jeff Sessions of Alabama, said he does not see a filibuster blocking the Sotomayor nomination, and Sen. Charles E. Grassley, Iowa Republican, predicted Wednesday that she would be confirmed.

Sen. Orrin G. Hatch, Utah Republican, said on CNN Wednesday he disagreed with Republicans who label the jurist a “racist.”

“No, I don’t agree with that and frankly, I think it’s a little premature and early because she hasn’t had a chance to explain some of these comments that she’s made,” he said, as the judiciary panel released a 10-page questionnaire for Judge Sotomayor to complete in advance of her hearings.

Still, conservative groups claim she’s a jurist with an attitude and unfit for the Supreme Court, imploring senators to look past her heritage and instead examine her record.

Judicial Confirmation Network posted a video going after Judge Sotomayor’s remark, insisting, “America deserves better.”

The White House provided reporters the chance to hear from legal colleagues familiar with Judge Sotomayor’s record, along with some of her law school classmates. They described her on a conference call as careful and cautious, saying she always pays strict attention to detail and offered literal readings of the law.

Mr. Gibbs also said Judge Sotomayor has begun outreach efforts on Capitol Hill, talking to Senate Majority Leader Harry Reid, Nevada Democrat, and Minority Leader Mitch McConnell, Kentucky Republican, along with Judiciary Chairman Sen. Patrick J. Leahy, Vermont Democrat, and Mr. Sessions.