I wouldn’t go that far to say it’s just 7 congress members. I primarily believe we’re that close due to the structure of our government. It favors the will of the minority(population wise) party(currently 1 step away from pure naked fascism) and all that’s needed is a small amount of 'bipartisan-ism" to achieve their goals while preventing the majority(population wise) party from implementing any of their agenda.

I’m sure you’re already aware, but for anyone that isn’t, this is a(poorly explained) example of the ratchet effect