How do the minor parties fit into descriptions of American politics?

Even though it may seem like minor parties don't have much of an effect on politics and elections, minor parties can actually make enough difference to change an election. Minor parties rarely win elections but are actually necessary to politics. The small amount of people that vote for minor parties could potentially cost enough for a major party to lose an election to the other major party. For example: If an election is 50/50 between Democratic and the Republican parties and 10 percent of the Democrats decide to vote for a minor party it would cost the Democrats the election. Hope this makes sense! Good luck!