aside from the fact that third parties in politics rarely ever work, some main effects of third partying politics in the US are candidates that have nothing to do with the two political parties already in office (democrat and republican). A system in which 2 major parties take control and there is no independent party (democrat and republican party). And then the winner take all system which is the party that receives the most votes takes over the office despite the other disagreeing party.
Our Queen was forced to sign the papers that authorized the United States to annex Hawaii with a pistol to her head and the threat of blood shed to her people. She was forced and imprisoned wrongfully, in her own royal palace. Had she not done that, her people would have been killed.