Challenge: With a POD after 1900, have a US that is around as leftwing as the current US is rightwing. Instead of a center-right party and a crazy-right party, there will be a center-left party and a crazy-left party. If it makes it easier the Democrats can become a regional party in the South but the two main parties must be on the left. Bonus points if the right has as little influence as the left do today in America (though big business will be hard to put down).