Mickey plumbs them:
At some point, GOP legislators may realize that it's in their individual interests, if they want to be reelected, to actually accomplish something, even if that means boosting Obama at the expense of whoever gets the GOP presidential nomination. This realization often takes a while to dawn, however. In 1995 and 1996, for example, Republicans initially resisted a reasonable compromise on welfare reform, preferring to have "the issue" to use against President Clinton in the Presidential race. Only at the second-to-last moment in 1996 did Newt Gingrich decidedespite pressure from the Dole campaignto actually try to enact a piece of legislation. The resulting bill was quite radical, by conventional Washington standardsbut even then the constant temptation was to pass a bill so extreme that Clinton would have to veto it (a process recounted in Ron Haskins' insider history, Work over Welfare)