From Ezra Klein:
Mark Schmitt adds
another perspective on the rise of the filibuster:
In terms of culture and custom, the turning point was almost certainly the previous health-reform debate, in 1993 and 1994. That's when Bob Dole, then the majority leader, made the phrase "You need 60 votes to do anything around here" his mantra, and when -- thanks to Bill Kristol's famous memo -- the idea of blocking major legislation for political reasons, rather than trying to get it revised to reflect your own policy preferences, took hold.
This is one of the explanations I favor for the rise of the filibuster: The Republican minority of the mid-'90s proved that a filibuster strategy was good politics. Kill the majority party's legislative agenda and you kill their standing in the eyes of the public, as well. America doesn't like losers, and the press has a useful tendency to blame legislative failure on the party that failed to pass the bill rather than the party that actually killed it.
http://voices.washingtonpost.com/ezra-klein/2009/11/even_lbj_would_be_stuck_if_he.html