This document provides an overview of the two-party political system in the United States. It discusses the roles and functions of political parties, including nominating candidates, influencing policy, and uniting government. It describes the core beliefs and platforms of the two major parties. It also outlines different types of party systems, such as single-party, two-party, and multi-party systems. The document uses the 1912 presidential election between Woodrow Wilson, Theodore Roosevelt, William Howard Taft, and Eugene Debs as an example of how third parties can influence electoral outcomes.