Rob Christenson has this mostly correct.
[Rep. Renee] Ellmers [R-NC] has a voting record to the right of Michele Bachmann. And she is under fire for being ideologically impure. This is why we have gridlock.
Most of the problem is that gerrymandered districts are uncompetitive districts, and that is only an amplification of an already existing geographical segregation that creates strong Republican districts even in states where Democrats draw the lines.
But strong unaccountable Republican districts wouldn’t be that big of a problem if the base of the party wasn’t making such unreasonable demands. There are, after all, strong Democratic districts. For example, in Philadelphia, Rep. Chaka Fattah won 89% of the vote, Rep. Bob Brady got 85%, and Rep. Allyson Schwartz got 69%. But you don’t see any of them worrying about a primary from their left.
The root cause of our country’s political problems is that the base of the Republican Party has gone stark-raving mad. Period.