Here's Jonathan Cohn's essay against the practice, written long before it was a cool Democratic position to have:
Fighting Bush's judicial nominees on the merits of their views will inevitably draw Democrats into at least a few cultural debates they probably don't want to have right now. But, in a sense, that's precisely the point. The filibuster has become a crutch for Democrats, a way to defend their programs and values without having to actually win over voters. This is the same essential mistake Democrats have made over and over again since the early '70s in relying upon courts to secure rights (like unfettered access to abortion) and promote reforms (like affirmative action) for which they hadn't yet built solid popular support. These court decisions eventually provoked political backlashes that have hobbled Democrats since and, in cases like gay marriage, probably set back the liberal cause by many years.
Indeed, it was a famous nineteenth-century senator from South Carolina, John C. Calhoun, who elevated the practice to a form of political philosophy. Calhoun argued that democracy would work best if the minority interests had a permanent veto over policy, a prerogative not unlike what the filibuster has become. But Calhoun championed such a system because, in the United States he knew, the South would never have as many congressional seats as the North. In other words, his side had become a permanent minority, a fate the Democrats risk if they keep yoking their political hopes to the filibuster.