The way I see it, American Government is like a marriage. The Republicans and Democrats are spouses. Now, to ascribe them normative historical gender roles, let's say the Republicans are the abusive husband and the Democrats are the battered spouse. The Republicans want out of the marriage, but the Democrats still think if they both just work together, then the marriage will be salvageable.
An abusive relationship always ends. It never suddenly turns into a good, wholesome, mutually supportive marriage. The two spouses either divorce - or eventually, one of them dies.