At its essential level, a political party is an extra-governmental conspiracy to control the government. Our constitutional system disperses power across three branches, two chambers of Congress, and federal, state, and local levels. The parties are centralizing forces, trying to unite all governmental power under the party banner. They accomplish this task when conspiring officials across the government coordinate their activities with others whose views are similar.
To be successful, a conspiracy requires a shared belief among the conspirators that their interests are linked - something to the effect of, "Whatever happens, we sink or swim together." This is really the only glue that binds a political party together. American party structures are very weak; partisans participate in the "conspiracy" only if they believe it will help them in the long run.He goes on to argue that Dems have nearly reached the tipping point--where political calculation will drive the party apart, limiting the leadership's ability to get anything substantial passed. Excellent analysis.