9.1: Introduction

Democrats cheer Kamala Harris as she accepts her party’s nomination for president at its 2024 national convention in Milwaukee.

It is difficult to think of American politics without thinking of parties. The American political landscape, from the choices voters make in elections to the arguments and alliances between politicians that play out in government, reflects the familiar battle lines drawn between Democrats and Republicans. These two parties permeate our politics so thoroughly that one could easily assume they are baked into our political system, as fixed and permanent as the Constitution.

Yet neither the Democratic Party nor the Republican Party — nor, for that matter, any party — is mentioned in the Constitution. No law passed by Congress establishes Democrats and Republicans as the principal combatants in the American political arena or decrees that almost all elected officials shall belong to these organizations. Nothing about the population of the United States suggests that it would naturally be represented by any two parties, let alone these two. In fact, many Americans express frustration that their political choices always seem to boil down to two options, neither of which they find particularly appealing.

Two-party dominance in the United States is neither a dictate of constitutional or statutory law nor a reflection of intrinsic social divisions It arose as a natural consequence of electoral rules, as groups of people coordinated around shared interests to maximize their influence on politics. Contrary to the expectations of the Founders, both major parties have survived more than a century of political upheaval, constantly adapting to maintain their competitiveness. To comprehend how any of America’s official institutions function, one must understand these unofficial institutions which shape so much of our politics.