U.S Election Format. America applies the winner-takes-all system in state elections. Hence, all seats are awarded to the candidate who wins the most votes regardless of the proportion of the votes. Moreover, some states such as Connecticut apply closed-primaries-voting system such that the public vote only in the primary elections of their respective political parties. Therefore, all the voters within such states register per party affiliations. A voter cannot change party affiliation to vote in a third party primaries if the voter had not initially registered with the given party.
Vast Resources of the Two Major Parties. The two major parties have a lot of resources (finances and human-power) to campaign unlike third party candidates. Hence, the two major parties are able to neutralize third party popularity by either incorporating their ideologies, or discrediting their views.
Ballot Laws. U.S has limiting ballot laws. A candidate is included in the ballot if the candidate pays large fees, and collects a large number of listed signatures as ballot requirements (Lumen Learning, par. 3). The requirements often limit the ability of third-party aspirants to be included in the ballot.
Debate Rules. The presidential debates require that a candidate must earn at least 15% of voters in national polls (McNally, par. 1). The requirement hinder minority-party candidates from getting the same public coverage as their counterparts in major parties since minority-party candidates rarely attain the 15% of national voters.
Minority parties represent a small percentage of American citizens with differing opinions from the two major parties. Despite the insignificant size of minority-party membership, such parties influence electoral outcomes by drawing voters from the two major parties. Furthermore, minority-party membership influence key issues addresses by parties during campaigns.
Lumen Learning. “Minor Political Parties.” LumenCandela: Boundless political Science. https://www.courses.lumenlearning.com/boundless-political-science/chapter/minor-political-parties/ Accessed 11 July 2020
McNally, Katie. “The third-party impact on American politics.” UVAToday. News.virginia.edu, 03 August 2016. www.news.virginia.edu/content/third-party-impact-american-politics%3famp Accessed 11 July 2020