Mathew Yglesias has brought renewed attention to Juan Linz’ thesis that our constitutional order is doomed. The basic idea is that if the chief executive and the legislature are elected separately, they can belong to different parties. In such cases, the legislature has every incentive to undermine the president, who will respond by expanding executive power. That situation will degenerate until the constitution fails, as it has in almost every presidential system outside the USA. See Yglesias’ Vox piece, “American Democracy is Doomed,” Jonathan Chait’s response (“There’s a Chance American Democracy Is Not Doomed“), and my own post “Are we seeing the fatal flaw of a presidential constitution?”

The Linz thesis requires an explanation for why the US system has not already collapsed after more than two centuries. The leading explanation is that we have never actually had two parties in Congress, notwithstanding the labels. Internal party splits have caused us to have at least three–and often four or more–effective parties. Thus presidents have been able to construct governing coalitions even when they face a majority of the opposite party. Reagan, for example, got most of his agenda through Tip O’Neil’s Democratic House because Southern Democrats voted with Republicans on key issues.

Our current situation looks unprecedented because the two parties are now perfectly polarized, with all the Democrats to the left of all the Republicans. Thus the Linz thesis explains paralysis and executive unilateralism under Obama and predicts worse to come.

But then we observe the Department of Homeland Security funding bill pass the Republican House with unanimous Democratic support. Democrats are also saying they would protect Speaker Boehner from a Tea Party effort to unseat him. (The Speaker is chosen by majority rule, so Boehner could hold his gavel with a mix of Republican and Democratic votes). These two examples suggest that Boehner is in the same place as O’Neil during the Reagan Administration. He leads a caucus that formally and rhetorically opposes the president. But sometimes the governing coalition in the House consists of 75 Republicans plus all the Democrats. Boehner is like a Prime Minister whose own party (the Center-Right) is smaller than its coalition partner (the Center-Left) but who alone can command more than 50% in votes of no confidence.

This situation only applies some of the time. Boehner does not like (and will not even acknowledge) his dependence on Democrats. It poses a serious problem for all Republicans, not just for Tea Partiers, because it cedes considerable power to the other party. Thus Republicans will make creative and sustained efforts to change the situation. But to the extent that it prevails, we will return to the classic US pattern instead of dissolving into a Linzian nightmare.