The current Republican party is just a photo negative of the Democrats. They both pander to special interest groups, just different ones. They both are heavily funded by corporate interests, just different ones. Both of them are into big government spending, just to different target constituencies. Neither organization is willing to stand up and address real issues. Look at the Democrats on peak oil.

Now this is not to say that there are people in both parties who are awake and thinking but the vast majority of both parties want to have their cake and eat it too. They only differ in their opinion of who gets the cake. The notion that there may not be any cake hasn't yet entered their stream of consciousness.

As for Republicans, they've bought into the false religion of endless growth. To challenge that challenges their core beliefs. Whenever you challenge someone's core religious beliefs you can expect fierce resistance, and the Republicans dedicated to endless growth are no exception to that rule.