This is a matter of math and political mechanics, not statutory or constitutional law. The framers of the US Constitution mostly didn’t even want parties to form, but parties formed almost instantly regardless. Then the reliance on single ballot plurality voting (first past the post) led to two parties. Even if a party has significant internal fractures like you find in both the Democratic and Republican parties, an equilibrium of two roughly equally sized parties is held because any other substantial party is pressured into a merger to produce an electoral majority. There have been several iterations of the two party system and every time it produced that equilibrium again.
I also recommend Democracy for the Few which is a great book discussing how US political system actually works. Any semblance of democracy is pure theatre.
This is a matter of math and political mechanics, not statutory or constitutional law. The framers of the US Constitution mostly didn’t even want parties to form, but parties formed almost instantly regardless. Then the reliance on single ballot plurality voting (first past the post) led to two parties. Even if a party has significant internal fractures like you find in both the Democratic and Republican parties, an equilibrium of two roughly equally sized parties is held because any other substantial party is pressured into a merger to produce an electoral majority. There have been several iterations of the two party system and every time it produced that equilibrium again.
The whole US system is basically an oligarchy. Here’s what a recent large scale study analyzing many decades of US policy concludes:
I also recommend Democracy for the Few which is a great book discussing how US political system actually works. Any semblance of democracy is pure theatre.