Speaking on CBS' "Face the Nation," Feinstein said Sunday she intends to vote against Alito's nomination, but saw no need for a Democratic filibuster.
"When it comes to filibustering a Supreme Court appointment, you really have to have something out there, whether it's gross moral turpitude or something that comes to the surface," she said. "This is a man I might disagree with, (but) that doesn't mean he shouldn't be on the court."
But Sen. Charles Schumer, D-N.Y., who has been a chief architect of the filibusters, said party leaders have not ruled out a filibuster.
"It's premature to say anything until we fully assess the record," he said on "Fox News Sunday."
President George Bush nominated Alito, a 55-year-old judge on the Philadelphia-based U.S. 3rd Circuit Court of Appeals, to replace retiring Justice Sandra Day O'Connor.