In anticipation of next week’s confirmation hearings for chief justice of the United States, a national anti-abortion group has launched an advertising campaign targeting Maine’s two senators, both of whom support abortion rights and remain publicly uncommitted on the nomination.

U.S. Sens. Olympia Snowe and Susan Collins, both R-Maine, are among 14 senators in eight states targeted by the National Pro-Life Alliance, which supports the nomination of Judge John G. Roberts.

The group, based in Washington, D.C., claims 600,000 members in its effort to overturn Roe v. Wade, the Supreme Court decision legalizing abortion in the United States.

The group’s executive director, Mary King, said Friday her group targeted the senators because she believed they were “likely to use a pro-abortion litmus test when voting on judicial nominees.”

Spokeswomen for both senators repeated Friday that they would not use any litmus test when assessing Roberts, and moreover, would not be swayed by advertising.

“Sen. Snowe takes her role in the confirmation of a Supreme Court justice very seriously and she will not be prejudiced against Judge Roberts,” said Snowe spokeswoman Antonia Ferrier. “She believes he is a very thoughtful and intelligent candidate and selection by the president.”

Collins, who met with Roberts Friday morning, expressed similar sentiments about the nominee, whom she called “impressive and straightforward in his responses” to her questions.

While Collins did not mention Roe v. Wade specifically, she did ask Roberts about his judicial philosophy on allowing legal precedent to stand even when he disagreed with the original decision.

Collins said she was satisfied with his response, which she said indicated a respect for precedent, including Roe v. Wade.

“I will reserve final judgment on the nomination, but I expect him to do very well,” Collins said.

Upon Chief Justice William Rehnquist’s death on Sept. 4, President Bush nominated Roberts to the position of chief justice. He has yet to nominate someone to fill the earlier vacancy created by the retirement of Sandra Day O’Connor.

After meeting with Roberts on Friday, Collins said she would have some suggestions for the president.

“I would like to see the president nominate a woman, but most of all, I want him to nominate the best person for the job,” she said.