The four types of minor parties in American politics are enduring minor parties, single-issue minor parties, candidate-centered minor parties and fusion minor parties. There are three minor parties that are recognized in more than 10 states in the US, including the Libertarian Party, the Green Party and the Constitution Party.
Enduring minor parties, such as the Libertarian Party, are much like major parties in that they have existed for a long time. However, they are much less successful in getting their candidates elected. An enduring minor party may lobby for candidates in state and federal offices but it tends to lack the organizational foundation and funding resources to get its candidates elected as often as the major parties.
Single-issue minor parties, which may also be referred to as ideological parties, promote a specific party agenda. The Green Party is an example of this. Founded in the 1980s, the Green Party based its ideology and focus on environmental issues. Candidate-centered minor parties have a central figure that rallies support around his or her political message.
Fusion minor parties can be single-issue or enduring minor parties that use cross-endorsement, where particular candidates are backed by more than one party, so they appear on the ballot with multiple party labels. Fusion minor parties can also be called alliance parties because in a sense they are forming an alliance with other parties by backing the same candidate. The practice of cross endorsement is only legal in eight states, however.