The term divide and conquer in politics refers to an entity gaining and maintaining political power by using divisive measures. This includes the exploitation of existing divisions within a political group by its political opponents, and also the deliberate creation or strengthening of such divisions.

The concept primarily refers to the practice of creating divisions between opponents to prevent them from uniting against a common foe, allowing the one who divides to gain or maintain political control. As a maxim, it is commonly recommended to political rulers. A secondary usage of the idea refers to the practice of "dividing one's own forces or personnel so as to deal with different tasks simultaneously." The exact wording of the idiom in English is varied, including divide and rule (mainly in British English but rarely used), divide and conquer (in American, the most common variation), divide and govern, and divide so that you may rule.

The phrase divide and conquer (from the latin divide et impera) first appeared in English around 1600.

Edward Coke denounces it in Chapter I of the Fourth Part of the Institutes of the Lawes of England, reporting that when it was demanded by the Lords and Commons what might be a principal motive for them to have good success in Parliament, it was answered: "Eritis insuperabiles, si fueritis inseparabiles. Explosum est illud diverbium: Divide, & impera, cum radix & vertex imperii in obedientium consensu rata sunt." ("You would be invincible if you were inseparable. This proverb, Divide and rule, has been rejected, since the root and the summit of authority are confirmed by the consent of the subjects.")

In a minor variation, Sir Francis Bacon wrote the phrase as separa et impera in a letter to James I of 15 February 1615. James Madison made this recommendation in a letter to Thomas Jefferson of 24 October 1787, which summarized the thesis of Federalist No. 10: "Divide et impera, the reprobated axiom of tyranny, is under certain (some) qualifications, the only policy, by which a republic can be administered on just principles."

Divide et impera is the third of three political maxims in Immanuel Kant's Perpetual Peace (1795), Appendix I, the others being Fac et excusa ("Act now, and make excuses later") and Si fecisti, nega ("If you commit a crime, deny it"): Kant refers to these tactics when describing the traits of “despotic moralists."

In politics, the concept refers to a strategy that breaks up existing power structures, and especially prevents smaller power groups from linking up, causing rivalries and fomenting discord among the people to prevent a rebellion against the elites or the people implementing the strategy. The goal is either to pit the lower classes against themselves to prevent a revolution, or to provide a desired solution to the growing discord that strengthens the power of the elites.

The principle "divide et impera" is cited as a common in politics by Traiano Boccalini in La bilancia politica.