Carol Platt Liebau nails it with this observation:
"It seems pretty significant that the left has to cast back to 1987 for a template of a successful derailing of a Supreme Court nomination. Because that's the first (and, really, the only) time they were successful in accomplishing it."
Go here for the rest of her post. BTW, if you haven't already book-marked Carol's blog, do so now because come January when the Alito hearings begin, she will be essential reading. She also posts here.