Democratic institutions are quarantine arrangements to combat that ancient pestilence, lust for tyranny: as such they are very useful and very boring.

[Die demokratischen Einrichtungen sind Quarantäne-Anstalten gegen die alte Pest tyrannenhafter Gelüste: als solche sehr nützlich und sehr langweilig.]

Friedrich Nietzsche (1844-1900) German philosopher and poet

Human, All Too Human [Menschliches, Allzumenschliches], Vol. 2, Part 2 “The Wanderer and His Shadow [Der Wanderer und sein Schatten],” aphorism 289 (1880) [tr. Holingdale (1986)]
    (Source)

(Source (German)). Alternate translations:

Democratic institutions are centres of quarantine against the old plague of tyrannical desires. As such they are extremely useful and extremely tedious.
[tr. Cohn (1913)]

Democratic institutions are quarantine mechanisms for that old pestilence, tyrannic lust. As such they are very useful and very boring.