The history of the 20th century shows that democracies sometimes must pursue seemingly undemocratic measures against those whose pursuit of power is motivated by a desire to abolish democracy altogether. Arguments that such a response is self-defeating do not withstand scrutiny.

BUDAPEST—One major lesson from the political catastrophes of the 20th century appears paradoxical: Democracies sometimes must pursue seemingly undemocratic measures against those who would cynically exploit the system to gain power and then abolish democracy altogether. The problem, of course, is that such measures invite charges that democracy has already abolished itself.