Final answer:
The Electoral College system favors a two-party system as it operates on a winner-take-all basis, making it hard for third-party candidates to win enough votes to secure the presidency. Historical examples, like the 1912 election influenced by the Progressive Party, show the difficulties faced by third parties. Voter behavior and campaign challenges further reinforce the dominance of the two major parties.
Step-by-step explanation:
The Electoral College system inherently favors a two-party system due to the winner-take-all nature of U.S. elections. In most states, the candidate with the majority of the popular vote takes all of the state's electoral votes. This structure makes it difficult for third-party candidates to gain traction because they must win outright in several states to have any chance at securing the presidency. Historical examples, such as the Progressive Party impact on the 1912 election, illustrate how third parties can shift outcomes but rarely succeed in winning national office.
Moreover, the system discourages voters from 'wasting' their vote on a candidate who is unlikely to win, steering them towards the two major parties. This mentality is further intensified by the substantial resources and mobilization capacities of the established parties. Additionally, third parties face challenges like securing ballot access and overcoming campaign finance hurdles, which are less problematic for the major parties.
While other factors like history and voting behaviors play a role, the winner-take-all Electoral College is the central mechanism through which the two-party system is perpetuated in the United States.