In his classic essay “The Perils of Presidentialism” (PDF) political scientist Juan Linz noted the striking fact that “the only presidential democracy with a long history of constitutional continuity is the United States . . . [a]side from the United States, only Chile has managed a century and a half of relatively undisturbed constitutional continuity under presidential government—but Chilean democracy broke down in the 1970s.” By contrast, many parliamentary democracies have managed to hold together for a long time.
Linz briefly treats the question of why presidential democracy, which basically doesn’t work, has managed to work in the United States:
But what is most striking is that in a presidential system, the legislators, especially when they represent cohesive, disciplined parties that offer clear ideological and political alternatives, can also claim democratic legitimacy. This claim is thrown into high relief when a majority of the legislature represents a political option opposed to the one the president represents. Under such circumstances, who has the stronger claim to speak on behalf of the people: the president or the legislative majority that opposes his policies? Since both derive their power from the votes of the people in a free competition among well-defined alternatives, a conflict is always possible and at times may erupt dramatically. Theme is no democratic principle on the basis of which it can be resolved, and the mechanisms the constitution might provide are likely to prove too complicated and aridly legalistic to be of much force in the eyes of the electorate. It is therefore no accident that in some such situations in the past, the armed forces were often tempted to intervene as a mediating power. One might argue that the United
States has successfully rendered such conflicts “normal” and thus defused them. To explain how American political institutions and practices have achieved this result would exceed the scope of this essay, but it is worth noting that the uniquely diffuse character of American political parties—which, ironically, exasperates many American political scientists and leads them to call for responsible, ideologically disciplined parties—has something to do with it.
Linz’s article was published in 1990 at a time when the observation about the lack of ideological coherent and rigorous discipline had been true for the overwhelming majority of American history. And, indeed, as recently as 1988 one could have witnessed moderate Democrat Joe Lieberman successfully challenging incumbent liberal Republican Senator Lowell Weicker with the support of, among others, William F Buckley, Jr.
But it turns out that Lieberman vs Weicker was something of a dying gasp of a political order that was rendered obsolete by the civil rights revolution. Twenty years later we find ourselves several congresses into a brave new world in which every single Democratic Party legislator is to the left of every single Republican Party legislator. In terms of partisan politics, in other words, we’ve become a normal country. But as Linz observed, the “normal” outcome for a country with our political institutions and ideologically sorted parties is constitutional crisis and a collapse into dictatorship.
So far it hasn’t happened here. The 1998-99 effort to impeach Bill Clinton was sufficiently unpopular that moderate Republicans wouldn’t vote for it. Al Gore chose not to contest the legitimacy of the Supreme Court ruling that handed the White House to George W Bush despite the fact that the electorate preferred Gore. And by 2007-2008, Bush was so unpopular that the Democratic Party leadership felt the wisest course was to avoid provoking a crisis and basically just wait him out. But we live in interesting times….