They don't have to cooperate at every level, they just have to cooperate in the main, which they do. That was my point. There are *cosmetic* differences between the parties, which is how they get people to buy into it, but ultimately they seek the same thing, and appear to have chosen to seek it together (for the moment).
Tuor
That's pure nonsense. Democrats are pro-choice. Republicans are pro-life. That's hardly "cosmetic".
Democrats want the Kyoto Treaty on Global Warming and they want the International Criminal Court. Republicans rolled both of those monstrosities back.
Likewise, the fight in the Senate over the 70 stalled judgeships is the antithesis of "cosmetic".
In your zest to view everything in America in a pro-third-party light, you've managed to miss some of the larger ideological wars of the last 40 years.