Everyone online seems to be using readily understood ideas to represent more complex ones. These are rarely appropriate, and always a gross over-simplification. But hey, I'll hop right on that bandwagon. I have a concept that is actually accurate however. One that will explain why the two-party system is broken beyond repair.
Imagine the entire country as a subdivision. A tidy little 50 home neighborhood. Each household has an average of 2 people. Most have only 1, but some have many more. Each house would be represented in the homeowners' association. Each house would be voting for, and representing their best interests, while preserving common ground, (your rights) and collecting dues from members, (taxes) and compromising when it came to benefiting the neighborhood as a whole. That is what the association rules (constitution) were written to represent. That was the vision of the founding fathers.
What we have now though, is a neighborhood ruled by warring street gangs. Let's call them Dueces and Royals. (In some neighborhoods this makes perfect sense). Neither side represents the interest of any household. Neither side is making the neighborhood any better. The protection money extorted from you does not go toward preserving parks (your rights), it goes toward marking territory in the common areas. The Dueces claim the territories (rights) they choose to represent, and the Royals other territories. Since neither side can acknowledge the other's claim is valid without sounding weak, no agreements for the common good are ever reached, and the parks (your rights) are destroyed by tagging. (claiming to represent your interests)
The rules, (constitution) such as they are, become free-floating, and subject to popular whim. Any attempt to stand alone, or to side with an outside gang, is met with bullying. Try telling a hardcore Democrat or Republican you are voting third party. They won't challenge you on a topic, or series of topics. They focus on the fact that you will be "Throwing your vote away", or voting for the other side, who are always talked about as though they are evil incarnate. You are either with us, or against us. They attempt to bully you into wearing their colors. The neighborhood, which was originally a nice place, becomes a dump; as neither side is interested in representing any individual household, nor the neighborhood, as a whole.
And the only way to solve urban blight is to bulldoze the entire neighborhood, and start over. This time with a fence (campaign laws that don't favor the two biggest parties) and a neighborhood watch. (active, informed voting against the two-party failure.) You could also move, but the other neighborhoods are generally far worse. The ones that are better have fewer public places, and higher association dues.