WASHINGTON – Maine Sens. Olympia Snowe and Susan Collins – both moderate Republicans – will play a key role in the Senate confirmation hearings of President Bush’s nominee for the U.S. Supreme Court.

The nomination of federal appellate judge Samuel Alito Jr. is expected to set off a showdown between Republicans and Democrats.

If confirmed, Alito would succeed Justice Sandra Day O’Connor, who has been a critical swing vote in cases involving abortion, affirmative action, campaign finance and the death penalty. He is being supported by conservatives but is meeting resistance from some Democrats who are talking about trying to block his confirmation.

Snowe and Collins play an important role because if Democratic opposition is unanimous, Republicans can afford to lose only a handful of votes from their 55-seat majority and still confirm Alito.

The senators reacted cautiously Monday on the confirmation process ahead.

“What I most hope is that this debate over one of the most important positions in our country can be conducted in a fair and civil manner,” Collins said. “The outside groups on both sides are so eager for a battle royal that it worries me that the debate may degenerate into an unpleasant, bitter, divisive and partisan showdown.”

Neither Collins nor Snowe were familiar with Alito or his decisions. Snowe said she was confident that his qualifications would be thoroughly and independently reviewed.

“I will evaluate Judge Alito based on his lengthy record, including all of his opinions, scholarship, judicial methodology and philosophy,” Snowe said.

Abortion looms as a major issue in the confirmation fight.

Alito was the lone dissenter in a 1991 case that struck down a Pennsylvania law requiring women seeking abortions to notify their spouses. But he also joined a majority in 2000 that found a New Jersey law banning late-term abortions unconstitutional.

Collins said although she disagreed with Alito’s dissent in the Pennsylvania case, she said she wants to discuss the decision with him and won’t judge him on his position on abortion alone.

“I need to get a better sense of his respect for precedent and his judicial philosophy. I don’t have that yet,” Collins said.