The institutional design through which democracies choose nominees who compete to become a nation’s chief executive is among the most consequential features in the design of democratic elections. Yet there is surprisingly little scholarship that explores this issue in detail. This Article provides both historical perspective on the evolution over time of the nomination process in the United States and comparative perspective on how other major democracies structure this process. The central organizing theme of this piece is the contrast between nomination processes that entail a central role for “peer review”—in which party leaders have a central voice in the selection of their parties’ nominees—and purely populist selection methods, in which ordinary voters completely control the selection of nominees and party figures have no special role. The first half of the Article is historical and focuses on the United States. In the 1970s, the United States shifted almost overnight from the methods that had been used for nearly 200 years to select party nominees, in which official representatives of the political parties played the major role in deciding the parties’ candidates for President, to a purely populist mode (primaries and caucuses) for selecting presidential nominees. The consequences of this dramatic transformation have manifested themselves in recent presidential nomination contests. In this Part, we seek to show both how radical the change was that was made in the 1970s and yet how accidental, contingent, and inadvertent this transformation was. The “framers” of these changes did not actually intend to create the system with which we ended up, in which the primaries and caucuses completely determine the parties’ nominees. The second half is comparative and explores how other major democracies structure the process of choosing party leaders and candidates for chief executive. This part shows that the U.S. system is an extreme outlier among major democracies: In no other democracy is the selection completely controlled by the mass of ordinary voters. Most other democracies use systems of pure peer review to select candidates for chief executive; or use systems that mix elements of peer review with popular participation; and in other ways continue to give official representatives of the parties much greater say than in the United States over the selection of the parties’ nominees for chief executive.