This dissertation presents a theory of the separation of powers centered on the President’s “power to persuade.” To meet the imperial public expectations placed on the office in the modern age, the President will reliably try to supplement his limited formal powers by convincing others to support his agenda, the people, party allies, and courts being the most important. The President’s techniques of persuasion fall into three regular categories. First, there is “going public,” or popular leadership, where the President turns the force of popular majorities into a tool for shaping policy or legislative outcomes. Second is executive law-making, whereby the President presses on party alliances to shape legislative content: drafting legislative proposals, mediating congressional debates, soliciting or taking advantage of broad delegations of authority. Finally, there is emergency management, whereby the President invokes security threats, real or contrived, to press his natural advantages of speed and decisiveness and claim exclusive power over governance. In three case studies from Latin America, I illustrate these techniques and how institutions have adapted in response. Some are success stories, some are not, but all offer evocative lessons in designing solutions to problems the U.S. also confronts. First, on popular leadership, I discuss Venezuelan democracy under populist Hugo Chavez, in which institutions that could be coopted and radicalized (the courts, the legislature) were, while those that could not (opposition governorships and state and local agencies) were duplicated and circumvented by a proliferation of loyalist organizations that effectively created a shadow “parastate.” Second, I give a critical assessment of Brazil’s spin on “cabinet government,” in which the makeup of the President’s Cabinet directly mirrors party balance in the legislature, thereby heightening the risks of quid-pro-quo policymaking, but also drawing a beneficial link between policy and representative democracy. Finally, I describe Colombia’s efforts to “judicialize” war, internal rebellion, and other economic or social crises by subjecting these to judicial review by the Constitutional Court, created in 1991 with a mandate to curb a historical legacy of presidential excess. Bringing these lessons home, I discuss how the American constitutional system is designed to absorb the shocks of populism, de facto presidential legislating, and the abuse of war powers, and how to channel their beneficial tendencies and contain their negative aspects. I argue that the U.S.’ robust civil society prevents the most egregious abuses of the “bully pulpit,” but that sweeping institutional capture can happen, and that the rule of law is threatened where institutions like the EPA or the FBI are not reformed, but tarred as illegitimate and unrepresentative. Second, I treat executive-legislative cooperation in governance and increases in delegated authority as essentially unavoidable, but argue that the concentration of power ought to be met by increased mechanisms of public oversight and participation that go beyond notice-and-comment, to include citizen initiatives. Finally, I argue that the exploitation of presidential war power needs to be made accountable to strict temporal and legal limits, and that in the American constitutional system, this would be most practically achieved by a new jurisprudence abandoning the political question doctrine with regard to invocations of the commander-in-chief power, especially those unsupported by congressional authorization.