How would a proportional voting system change the American politics?
And associated political spectrum, if similar to the Australian system described here [1]
[1] https://i.redd.it/l9pbiv3fm4ka1.jpg
It wouldn't change the underlying political spectrum, but it would change the politics by introducing the democratic principle of "one person one vote", which is why it isn't going to happen (at least in my remaining actuarial lifetime).