"We know that extremist demagogues emerge from time to time in all societies, even in healthy democracies. The United States has had its share of them, including Henry Ford, Huey Long, Joseph McCarthy, and George Wallace. An essential test for democracies is not whether such figures emerge but whether political leaders, and especially political parties, work to prevent them from gaining power in the first place—by keeping them off mainstream party tickets, refusing to endorse or align with them, and when necessary, making common cause with rivals in support of democratic candidates. Isolating popular extremists requires political courage. But when fear, opportunism, or miscalculation leads established parties to bring extremists into the mainstream, democracy is imperiled. Once a would-be authoritarian makes it to power, democracies face a second critical test: Will the autocratic leader subvert democratic institutions or be constrained by them? Institutions alone are not enough to rein in elected autocrats. Constitutions must be defended—by political parties and organized citizens, but also by democratic norms. Without robust norms, constitutional checks and balances do not serve as the bulwarks of democracy we imagine them to be. Institutions become political weapons, wielded forcefully by those who control them against those who do not. This is how elected autocrats subvert democracy—packing and “weaponizing” the courts and other neutral agencies, buying off the media and the private sector (or bullying them into silence), and rewriting the rules of politics to tilt the playing field against opponents. The tragic paradox of the electoral route to authoritarianism is that democracy’s assassins use the very institutions of democracy—gradually, subtly, and even legally—to kill it. America failed the first test in November 2016, when we elected a president with a dubious allegiance to democratic norms. Donald Trump’s surprise victory was made possible not only by public disaffection but also by the Republican Party’s failure to keep an extremist demagogue within its own ranks from gaining the nomination."