The United States may have avoided the worst possible outcome for a presidency, but other Linzian observations have fresh relevance today. He made the case that since you can run for president without climbing your way up a party ladder – unlike vying to be prime minister – the office appeals to outsider candidates with no allegiance to the political system, who can gain popularity by railing against that system, diminishing trust in it. Presidents are inclined to insist that they and not the fragmented legislature speak for “the people,” as a way of aggrandizing their power. (Trump’s “silent majority” and “real America” rhetoric fits this pattern.) At the same time, they have less incentive than a legislature to represent the interests of the minority party or parties. Unlike in a parliamentary system, there is no penalty for appointing toadies and hyperpartisan hacks to the Cabinet…

Linz also pointed to America’s “uniquely diffuse” political parties, each containing members with a wide variety of views, which facilitated ad hoc compromises on policy, both within Congress and between Congress and the president. But both of these observations now seem dated. Opinions may differ on what constitutes moderation, but few would now argue that extremism can never win in the United States. And even as Linz was writing, the era of flexible parties was approaching its end. Democrats and Republicans diverged in the 1990s, growing more internally unified and more hardened against each other (there are virtually no socially liberal Republican politicians, for example, or antiabortion Democrats).