Abstract: The maxim “divide and conquer” (divide et impera) is frequently invoked in legal theory and the social sciences. We suggest that the maxim is a placeholder for a complex of ideas related by a family resemblance, but differing in their details, mechanisms and implications. We provide an analytic taxonomy of divide and conquer mechanisms in the settings of a Stag Hunt Game and an indefinitely-repeated Prisoners’ Dilemma. These two games both illustrate a tension between the social desirability of cooperation and the private incentives for safety and short-run gains. Next, we describe the role of third parties who are not themselves players of these games but who will be harmed if the players cooperate. In particular, we explore a variety of divide-and-conquer strategies – including the sabotage of communication channels, the payment of bribes, and the imposition of penalties – that effectively prevent cooperation among the players of these games. A number of applications are considered, including labor law, constitutional design and the separation of powers, imperialism and race relations, international law, litigation and settlement, and antitrust law. Conditions under which divide and conquer strategies reduce or enhance social welfare, and techniques that policy makers can use to combat divide and conquer tactics, are also discussed.