divide and conquer

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb A combination of political, military and economic strategies that aim to gain and maintain power by breaking up larger concentrations of power into chunks that individually have less power than the one implementing the strategy.
• verb as imperative, proverb In order to rule securely, don't allow alliances of your enemies.
• noun A strategy for achieving political or military control.
• noun computing An algorithm design technique applied to various algorithms, such as quicksort, that solve a problem by splitting it recursively into smaller problems until all of the remaining problems are trivial.