I am aware of the first-past-the-post system, but UK and Canada also have the same but their third parties gain national/federal seats.
In the US, it’s always either Democrats or Republicans. There are third parties on state and county level but never succeed on the national level. How come? Is the electoral college somehow impeding third parties?
Just from personal observation it seems like it’s always too little, too late. I never seem to hear or see anything about third parties until right before an election, where they seemingly step out of the bushes and go “Hey, what about me?”.