WASHINGTON -- As if they were launching campaigns for a national political candidate, conservative and liberal organizations yesterday scurried to mobilize their troops for the coming battle over the confirmation of John G. Roberts Jr. to the U.S. Supreme Court, sending out e-mail alerts, conducting Capitol Hill rallies and filling Web sites with opinion and information.

Several dozen members of women's groups, holding signs reading "Our Bodies, Our Rights" and coat hangers stating "Keep this out of my uterus," marched in front of a U.S. Senate office building, urging senators to oppose Roberts because of his record on abortion rights.

Progress for America, a conservative group, unveiled a 30-second television ad designed to build support for Roberts by "introducing" him to the American public as a "brilliant" lawyer and "fair" judge. The linchpin of an initial $1 million, one-week campaign, the ad ends by asking viewers: "Shouldn't a fair judge be treated fairly?" and exhorting them to write their senators in support of Roberts.

Today, members of the left-leaning MoveOn.Org Political Action will gather signatures on anti-Roberts petitions in 165 cities, including Pittsburgh. MoveOn members will circulate the petitions in front of grocery stores, restaurants and community centers.

Interest groups on both sides also are making extensive use of the Internet to quickly reach supporters and influence public opinion on a 24/7 basis -- something that wasn't available the last time the Senate debated a Supreme Court nominee 11 years ago.

Within an hour of President Bush announcing Roberts as his choice late Tuesday evening, for example, Progress for America went "live" with the Web site judgeroberts.com. Over the past few weeks, the group had registered domain names for Web sites for 30 possible Supreme Court candidates, said spokeswoman Jessica Boulanger.

In the 12 hours after Bush's announcement, members of the liberal group People for the American Way sent 30,000 e-mails to senators through the Web site saveourcourt.org urging them to withhold judgment on Roberts until more is known about his stance on key issues such as abortion, civil rights and the environment.

"The Internet has taken the conversation out from the dinner table to the wider world," said Carol Darr, director of the Institute for Politics, Democracy and the Internet at George Washington University. "It's going to be real interesting to watch."

For both sides, the stakes are high, and considerable cash and political capital will be spent before the Roberts nomination battle is over. Progress for America said it is prepared to spend $18 million on advertising and grass-roots efforts to promote the nomination.

Opponents of Roberts also are working to raise money so they can get their message out, especially to young women who they say will be most affected if the U.S. Senate approves the nomination.

Abortion is expected to be a key factor in the debate over Roberts, both sides agree. Abortion rights groups are particularly concerned about Roberts' record, pointing out that he argued on behalf of "Operation Rescue," a group that aggressively attempts to persuade women against abortions.

As a government lawyer in the first Bush administration, Roberts argued for scrapping Roe v. Wade, the 1973 ruling legalizing abortion, the groups note. Years later, in his 2003 confirmation hearing to become a federal appeals court judge, however, Roberts called Roe v. Wade "the settled law of the land," although as a Supreme Court judge he could vote to overturn it.

"With 'Roe' hanging by a fifth vote, we have a right to know exactly where he stands," said Eleanor Smeal, president of the Feminist Majority. "We want to make sure he won't be confirmed as a stealth candidate."

Conservative groups, meanwhile, spent yesterday highlighting Roberts' "outstanding" education and legal career.

"This man's credentials are the dream of every lawyer on the planet," said Jan LaRue, chief counsel of Concerned Women For America.

Conservatives also praised Roberts' record in private practice and as a government lawyer.

"I think [Roberts' nomination] is a big victory for anybody who thinks that the Supreme Court has badly overstepped its legitimate authority," said Sean Rushton, executive director of the Committee for Justice.

Paul Rosenzweig, a legal expert at the conservative Heritage Foundation, said he believes that interest groups on both sides will be "much less important than they think" because of Roberts' "stellar" credentials.

"I think it's going to be a pretty easy run [in the Senate confirmation process] for John Roberts, and that all of the unhappiness from some public interest groups and joy from others won't come down to much," Rosenzweig added.

Opponents of Roberts' nomination acknowledge that their task also will be made more difficult by Roberts' likeable personality and experience as a Washington insider who knows people on both sides of the Senate aisle.

"No doubt these things give him an edge," said Kim Gandy, president of the National Organization for Women. "No doubt he is a nice guy. So he will smile while reversing 'Roe.' "

Although some groups immediately launched anti-Roberts campaigns, others, such as the People for the American Way, are holding their fire and asking senators to do likewise.

"We haven't opposed Roberts, although we have expressed very serious concerns about his troubling record," said Elliot Mincberg, vice president and legal and education policy director of People for the American Way Foundation. "It may well turn into opposition at some point.

"But we think it is important to prevent the kind of rush to judgment that the White House and some of the far right are trying to push on the nomination. I think that, for a nomination like this one, for someone who has a relatively sparse record, the hearings are absolutely critical."