Final answer:
The United States is characterized by a two-party system, with the Democratic and Republican parties being the major political forces. Minor parties exist but face significant challenges in gaining political control due to electoral rules.
Step-by-step explanation:
The United States is characterized by a two-party system. While other parties exist, the political landscape is dominated by the Democratic and Republican parties. Minor or third parties such as the Green Party and Libertarian Party do participate in elections, but the electoral rules and the winner-take-all Electoral College system make it extremely challenging for these parties to gain significant political control. Throughout American history, although parties' names and forms have changed, the two-party system has remained a consistent feature. This system is deeply rooted in U.S. history, stemming from early disagreements about the power of the federal government, with subsequent evolution based on ideological positions and constituency. Third parties do exist, but their influence is limited, and the major political contestation occurs between the two major parties, which seek to build broad coalitions to win elections and influence public policy.