By John Whitesides
WASHINGTON (Reuters) - Senate Republicans warned on Sunday they could raise procedural roadblocks to any Supreme Court nominee they consider outside the judicial mainstream, although one prominent Republican said such an effort was unlikely.
President Barack Obama will name a nominee to replace retiring liberal Supreme Court Justice John Paul Stevens in the next few weeks, sparking a potential confirmation battle in the run-up to November's congressional elections.
Senate Republicans said they would not rule out using the procedural roadblock known as a filibuster to try to prevent a confirmation vote on any nominee they considered a liberal activist.
"If it's somebody like that, clearly outside of the mainstream, then I think every power should be utilized to protect the Constitution," Senator Jeff Sessions, the ranking Republican on the Judiciary Committee, told NBC's "Meet the Press."
Jon Kyl, the Senate's No. 2 Republican, played down the likelihood and said it would require an extraordinary circumstance.
"It is unlikely that there would be a filibuster, except if there is an extraordinary circumstance," Kyl told ABC's "This Week" program. "I'm not going to take it off the table. But I think it can easily be avoided."
The Senate traditionally has not used procedural means to block Supreme Court nominees. A group of 14 centrist Republican and Democratic senators agreed in 2005 not to filibuster judicial nominees except in extraordinary circumstances.
"If the president picks someone from the fringe instead of from the middle, or if he picks someone who will apply their feelings instead of applying the law, then that might be an extraordinary case," Republican Senator Lamar Alexander said on "Fox News Sunday."
Obama's fellow Democrats control 59 seats in the 100-member Senate, and would have to muster 60 votes to break the roadblock and clear the way for a direct vote on the nominee.
The most prominent early candidates for the Supreme Court opening include Solicitor General Elena Kagan and U.S. appeals court judges Diane Wood and Merrick Garland.
Senator Patrick Leahy, Democratic chairman of the Judiciary Committee, predicted that the new justice would be confirmed by the Senate this summer and take the bench for the beginning of the next court term in October.
"I don't think there is going to be any kind of filibuster," Leahy told NBC, calling it a "lazy" approach to confirmation. "The American people elect us to vote 'yes' or 'no,' not to vote 'maybe.'"
Democratic Senator Charles Schumer said "it's just about a certainty that the president will nominate someone in the mainstream, so the likelihood of a filibuster is tiny."
Obama is expected to choose someone who will follow the same basic judicial philosophy as the liberal Stevens and is unlikely to change the court's overall ideological balance, which for years has been closely divided with five conservatives and four liberals.
Supreme Court appointments have sometimes become major political battles. This year's debate will come amid the campaign for control of Congress and in an atmosphere left polarized by the bitter debate over healthcare legislation.
"If we have a nominee that evidences a philosophy of 'judges know best,' that they can amend the Constitution by saying it has evolved, and effectuate agendas, then we're going to have a big fight about that," Sessions said.
Obama named his first Supreme Court justice last year, picking Sonia Sotomayor as the court's first Hispanic to replace retiring Justice David Souter. She was confirmed on a largely party-line vote of 68-31.
(Additional reporting by Paul Simao; Editing by Will Dunham)