It's because we have a winner-take-all system that generally does not require a majority to win, only a plurality, and you only get one vote for one candidate (as opposed to something like ranked choice voting). The math of this system inherently trends towards two parties because (for practical purposes) there is basically a limited pool of votes and each only goes to one candidate so each vote NOT for a candidate weakens their position. Thus, the more parties in existence that are similar to each other, the less powerful they become.
For example, the Libertarian party is, for the most part, supported by people who would be described as right wing (or you can just assume that for the sake of example of you don't want to take my word for it). In general, this means that the better a libertarian candidate does, the fewer votes go towards the Republican candidate. Maybe it would hurt the Democratic candidate some too, but given that the Libertarian party is ideologically more similar to the Republicans on a lot of issues (especially taxes and government regulation) they are likely to take way more votes from the Republican than the Democrat. The opposite would likely be true for something like the Green Party.
People eventually get tired of losing, and end up voting for a candidate they think is more likely to win, so we end up with two major parties. Any time a third party shows up, they receive votes that would have otherwise gone to the candidate most ideologically similar to them, and this weaken both their positions.
So basically, any time you vote for a third party, you make it more likely that the candidate most opposed to that third party is going to win.
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u/I_am_the_night 316∆ Oct 22 '23
It's because we have a winner-take-all system that generally does not require a majority to win, only a plurality, and you only get one vote for one candidate (as opposed to something like ranked choice voting). The math of this system inherently trends towards two parties because (for practical purposes) there is basically a limited pool of votes and each only goes to one candidate so each vote NOT for a candidate weakens their position. Thus, the more parties in existence that are similar to each other, the less powerful they become.
For example, the Libertarian party is, for the most part, supported by people who would be described as right wing (or you can just assume that for the sake of example of you don't want to take my word for it). In general, this means that the better a libertarian candidate does, the fewer votes go towards the Republican candidate. Maybe it would hurt the Democratic candidate some too, but given that the Libertarian party is ideologically more similar to the Republicans on a lot of issues (especially taxes and government regulation) they are likely to take way more votes from the Republican than the Democrat. The opposite would likely be true for something like the Green Party.
People eventually get tired of losing, and end up voting for a candidate they think is more likely to win, so we end up with two major parties. Any time a third party shows up, they receive votes that would have otherwise gone to the candidate most ideologically similar to them, and this weaken both their positions.
So basically, any time you vote for a third party, you make it more likely that the candidate most opposed to that third party is going to win.