Acrimony and hyperpartisanship have seeped into every part of the political process. Congress is deadlocked, and its approval ratings are at record lows. America's two main political parties have given up their traditions of compromise, endangering our very system of constitutional democracy. And one of these parties has taken on the role of insurgent outlier; the Republicans have become ideologically extreme, scornful of compromise, and ardently opposed to the established social and economic policy regime.

Here, congressional scholars Thomas Mann and Norman Ornstein identify two overriding problems that have led Congress - and the United States - to the brink of institutional collapse. The first is the serious mismatch between our political parties, which have become as vehemently adversarial as parliamentary parties, with a governance system that, unlike a parliamentary democracy, makes it extremely difficult for majorities to act. Second, while both parties participate in tribal warfare, both sides are not equally culpable. The political system faces what the authors call "asymmetric polarization", with the Republican Party implacably refusing to allow anything that might help the Democrats politically, no matter the cost.