Technically, the Two Party system isn't actually a thing. It is instead simply the work of Market Forces. Multiple competitors in any market, shall result in that market being split between two competitors and an also ran. Then Market Power, if abused, shall prevent any actual competition to the duopoly. Something truly disruptive is required to change that. ATM the US has a pair of more or less captured political parties market. They are in no way an official part of the Government. Nothing in the Constitution empowers them. They should have no power at all. No say in who runs nor any influence beyond whatever PR for issues they advocate. However, they worked out how to make getting elected very profitable, and thus very expensive. Rather quickly money called all the shots. Then the manipulated monster these very wealthy and connected folks created to get elected, lost their minds because a "them" got elected President, and the "useful idiot" they brought in to pacify things with some good Fascism, turned out to be in multiple pockets and beholden to no one but himself. There is your US Political History tldr;