This term refers to any political group- other than democrats and republicans- that attempts to get their candidates elected to public office.

Third party.

Explanation:

Third parties have sometimes launched large campaigns and have won public offices, but have not obtained significant or consistent representation in the federal government.  A third party could change the state’s winner in one of these states by gaining enough votes that would have otherwise gone to a major party. If the election is equally close this time, a third party potentially could determine the outcome by claiming only a small share of the vote. The most likely scenario for a third party influencing the election could be upsetting a close race

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