An excellent synopsis from Norm Ornstein:
Today’s Tea Partiers recognize that they share a similar governing philosophy with their forebears [of 1994], but they believe almost uniformly that the Gingrichites sold out too quickly, blinking unnecessarily when the political heat got turned up.
To which Jonathan Bernstein adds two other excellent points:
The first is the conservative closed-information loop: It’s very likely that Tea Partyers in Congress really don’t realize how unpopular many conservative ideas are with swing voters because the news sources they’ve listened to for years never happen to mention it. The other key factor was the 2010 elections, and in particular the primary challenges to incumbents such as Lisa Murkowski and Bob Bennett. Normally, the reality check on fantasies about the popularity of fringe partisan ideas comes when politicians start thinking of Election Day. However, when the Election Day that looms largest in the imaginations of those politicians is the primary, then they’re pushed toward those fringe positions, not away from them.
To which I'd add yet a third point: The GOP's creeping institutionalization of rank amateurism in American politics.
This Everyman mania started faintly with the GOP's temper-tantrumed 22nd Amendment, which limited U.S. presidents to two terms; heaven forfend we should ever be oppressed by another FDR, whose prolonged political and professional splendor in the Oval Office put every Republican president since Lincoln to ineffable shame. Later came the Barry Goldwater squalor about the need for simplicity to trump complexity in the politico-policy arena: an unmistakable call for right-winging rubes void of analytical backgrounds to join electoral battle, which is precisely what the subsequent New Right -- father of the contemporary Tea Partying Right -- did.