United States

There are several reasons for the failure of minor parties and the resilience of America’s two-party system. In order to win a national election, a party must appeal to a broad base of voters and a wide spectrum of interests. The two major parties have tended to adopt centrist political programs, and sometimes there are only minor differences between them on major issues, especially those related to foreign affairs. Each party has both conservative and liberal wings, and on some issues (e.g., affirmative action) conservative Democrats have more in common with conservative Republicans than with liberal Democrats. The country’s “winner-take-all” plurality system, in contrast to the proportional representation used in many other countries (whereby a party, for example, that won 5 percent of the vote would be entitled to roughly 5 percent of the seats in the legislature), has penalized minor parties by requiring them to win a plurality of the vote in individual districts in order to gain representation. The Democratic and Republican Party candidates are automatically placed on the general election ballot, while minor parties often have to expend considerable resources collecting enough signatures from registered voters to secure a position on the ballot. Finally, the cost of campaigns, particularly presidential campaigns, often discourages minor parties. Since the 1970s, presidential campaigns (primaries and caucuses, national conventions, and general elections) have been publicly funded through a tax checkoff system, whereby taxpayers can designate whether a portion of their federal taxes (in the early 21st century, $3 for an individual and $6 for a married couple) should be allocated to the presidential campaign fund. Whereas the Democratic and Republican presidential candidates receive full federal financing (nearly $75 million in 2004) for the general election, a minor party is eligible for a portion of the federal funds only if its candidate surpassed 5 percent in the prior presidential election (all parties with at least 25 percent of the national vote in the prior presidential election are entitled to equal funds). A new party contesting the presidential election is entitled to federal funds after the election if it received at least 5 percent of the national vote.

Both the Democratic and Republican parties have undergone significant ideological transformations throughout their histories. The modern Democratic Party traditionally supports organized labour, minorities, and progressive reforms. Nationally, it generally espouses a liberal political philosophy, supporting greater governmental intervention in the economy and less governmental regulation of the private lives of citizens. It also generally supports higher taxes (particularly on the wealthy) to finance social welfare benefits that provide assistance to the elderly, the poor, the unemployed, and children. By contrast, the national Republican Party supports limited government regulation of the economy, lower taxes, and more conservative (traditional) social policies. In 2009 the Tea Party movement, a conservative populist social and political movement, emerged and attracted mostly disaffected Republicans.

A Tea Party rally in Sacramento, California, September 12, 2010.Steve Yeater/AP

American presidential election, 1960Results of the American presidential election, 1960Sources: Electoral and popular vote totals based on data from the Office of the Clerk of the U.S. House of Representatives and Congressional Quarterly's Guide to U.S. Elections, 4th ed. (2001).Encyclopædia Britannica, Inc.