After a week of protests by conservatives, an abortion-rights group said Thursday night it is withdrawing a television advertisement linking Supreme Court nominee John Roberts (search) to violent anti-abortion activists.

"We regret that many people have misconstrued our recent advertisement about Mr. Roberts' record," said Nancy Keenan, president of NARAL Pro-Choice America (search).

"Unfortunately, the debate over that advertisement has become a distraction from the serious discussion we hoped to have with the American public," she said in a letter Thursday to Sen. Arlen Specter (search), R-Pa., who had urged the group to withdraw the ad.

Specter, himself an abortion-rights supporter as well as chairman of the Senate Judiciary Committee that will question Roberts next month, earlier Thursday had called the ad "blatantly untrue and unfair."

The NARAL ad criticizes Roberts and links him with violent anti-abortion protesters because of the anti-abortion briefs he worked on as a government lawyer.

"The NARAL advertisement is not helpful to the pro-choice cause which I support," Specter said in a letter to Keenan.

Keenan's response said the group will replace the ad with one that "examines Mr. Roberts' record on several points, including his advocacy for overturning Roe v. Wade (search), his statement questioning the right to privacy and his arguments against using a federal civil rights law to protect women and their doctors and nurses from those who use blockades and intimidation."

The original ad has been airing on broadcast television in Maine and Rhode Island and on CNN.

At least one television station had already refused to run the ad. Mike Young, vice president and general manager of WABI in Bangor, said his station ran the ad before deciding to pull it Thursday after receiving a challenge from the Republican National Committee.

"After careful thoughtful analysis, we determined the ad was at worst false, and at best misleading," he said.

Conservatives and Roberts supporters have been calling all week for NARAL to pull the ad.

NARAL had planned a $500,000 campaign to show the ad for two weeks.

"This ad grossly distorts the record of John Roberts from start to finish," said former Judiciary Chairman Orrin Hatch, R-Utah. "It has only one goal: to associate John Roberts with violent extremists."

Senate Democrats have not taken a position on the ad. Sen. Patrick Leahy of Vermont, the Judiciary Committee's top Democrat, told The Associated Press that ads for and against Roberts won't sway senators weighing the confirmation.

"There has been much furor over these ad campaigns, but I believe that television advertisements are not the point, and should not be the focus of debate or discussion," Sen. Charles Schumer, D-N.Y., said Thursday. But Schumer said he would ask Roberts about the constitutionality of abortion clinic protesting at his confirmation hearing.

In 1991, Roberts helped write — on behalf of the government — a Supreme Court brief in Bray v. Alexandria Women's Health Clinic. In that case, the court limited the federal help available to abortion clinic owners who seek to stop blockades by protesters.