Our two-party system has, on the whole, served us well. But there is nothing particularly sacred about it, and the Founders didn’t (to put things mildly) want one:
There is nothing which I dread so much as a division of the republic into two great parties, each arranged under its leader, and concerting measures in opposition to each other. This, in my humble apprehension, is to be dreaded as the greatest political evil under our Constitution.
John Adams, letter to Jonathan Jackson (2 October 1780)