Frances Lee, a political scientist at the University of Maryland, states a truth that should be obvious, but that many analysts nevertheless miss:
[T]he period since 1980 stands out as the longest sustained period of competitive balance between the parties since the Civil War. Our politics is distinctive for its narrow and switching national majorities. Nearly every recent election has held out the possibility of a shift in party control of one institution or another. Looking back, the period most similar to the present was the Gilded Age (1876-1896), another era of close and alternating party majorities, as well as of ferocious party conflict.
Competition fuels party conflict by raising the political stakes of every policy dispute. When control of national institutions hangs in the balance, no party wants to grant political legitimacy to its opposition by voting for the measures it champions. After all, how can a party wage an effective campaign after supporting or collaborating with its opposition on public policy? Instead, parties in a competitive environment will want to amplify the differences voters perceive between themselves and their opposition. They will continually strive to give voters an answer to the key question: “Why should you support us instead of them?” Even when the parties do not disagree in substantive terms, they still have political motivations to actively seek and find reasons to oppose one another. In an environment as closely competitive as the present, even small political advantages can be decisive in winning or losing institutional majorities.
This is one of the ways in which, per Lee, “today’s political context disincentivizes successful bipartisan negotiation.”
But you’ll notice that in many conversations about partisan polarization, you’ll hear that Republicans are the most egregious offenders, or that when Democrats make unattractive compromises, it is out of fear of right-wing demagoguery. For example, Democrats might have chosen a less “corporatist” approach to the Affordable Care Act, but they were forced into a “kludgey” approach by intransigent conservatives.
Consider the same basic story applied to a different case. During the George W. Bush presidency, the White House sought to couple the creation of a new prescription drug entitlement with reform of the core Medicare entitlement; the goal was to move Medicare from an open-ended benefit to a premium support system, a transition that conservatives believed would eventually yield substantial savings. But vulnerable Republican lawmakers, fearing Democratic scare-mongering, balked at Medicare reform, and the Bush administration, recognizing that a failure to create a prescription drug entitlement might endanger the president’s reelection effort, chose to take the less ambitious approach. And so one can blame Democrats for boxing Republicans into a corner, “forcing” them to create a deficit-expanding entitlement without securing commensurate savings elsewhere in Medicare through structural reform.
This isn’t the narrative we generally hear. Rather, we hear from the Tea Party right that big government Republican sellouts were hellbent on growing the welfare state to win the favor of the Georgetown cocktail party set while liberals (including those who made premium support politically toxic, presumably because they thought it was a bad idea) damned the GOP for its anti-spending hypocrisy. Notice a key aspect of this story: liberals opposed premium support because they tend to be somewhat more skeptical of the use of market mechanisms in certain domains (health and education in particular) than in others, and they feared that it would degrade the quality of the medical care available to older Americans. Some liberals might have also recognized that had Republicans succeeded in passing a premium support reform of Medicare, they would have handed conservatives a significant ideological victory — they would have succeeded, for better or for worse, in making a dent in the growth of public social expenditures. Denying the right a victory made sense to liberals on substantive grounds (they think premium support is bad), on ideological grounds (they are opposed to what they see as the nihilistic anti-statism of spending hawks), and on political grounds (let’s make it costly for them to achieve a political victory, and perhaps drive a wedge between the elected GOP and its ideological true believers). My impression is that ideologically liberal voters seem to be more forgiving of Democratic politicians than ideologically conservative voters are of Republican politicians, which could reflect the fact that ideological liberalism is in some sense more transactional (half a loaf is better than none) than ideological conservatism, which tends to be more cosmic (you’re either for freedom or against it, and a revolving cast of right-of-center media personalities, activists, and elected officials are constantly reformulating the litmus tests).
All of this this is to say that some of the most unattractive aspects of the Republican approach to governance, like the most unattractive aspects of the Democratic approach to governance, are the products of a highly competitive political environment. Committed Democrats want to move from a highly competitive political environment to one in which Democrats are dominant and Republicans evolve into a me-too party, and committed Republicans are rooting for a mirror-image scenario. Scorched-earth campaigning is overdetermined.