Thirty years ago, a political scientist named Juan Linz wrote a series of influential essays articulating a link between presidencies and democratic backsliding, including by coup. In contrast to parliamentary systems, where legislators choose the chief executive (usually called a prime minister), presidential systems produce rival centers of power and reduce incentives for compromise, Linz argued. When the legislature and the president can each claim an electoral mandate, intractable differences might tempt one or the other to “knock on the barracks door” in search of military allies; a violent dissolution of democracy could be the result. Parliamentarianism, by contrast, provides a safety valve because the legislature has the ability to remove the executive, typically by simple majority vote. Even when things don’t get to the stage of full meltdown, presidencies tend to heighten tensions in polarized societies, Linz contended, encouraging extreme political views rather than compromise, and often producing political gridlock.