Given the arguments against first past the post voting systems, I'd like to know what could be done to change them. However, there's a difficulty with proposing such a change to the system, and that's how it favors incumbent political parties. As the people who write laws enjoy benefits from the existing first past the post setup, they are not incentivized to change it.
Essentially, only 2 major national political parties exist here in the United States, arguably in part due to the first past the post setup of our voting system. If that's so, neither has any reason to move to replace first past the post.
How can citizens challenge such a situation to effect a change in the voting system?