I don't think you will have to wait 20 years for your revolution but the US won't become the UK. The white supremacists are armed and ready and spoiling for a fight - so much for live and let live - and outbreaks of violence will much more likely be race-based than political.
I sure hope you are right about the first part, the US not becoming the UK, but I don't think you will be. You are definitely wrong about things being race-based. That is just an unhappy side effect of where racial divides, really cultural divides, fall politically. And you put too much stock in the dramatic images of militia-wannabees, both black and white, parading around with guns. While it is wonderful imagery for selling news broadcasts it does not represent the rank and file American, black, white or any other color or stripe. The socialists have their pawns and move them around the chessboard quite well. The capitalists (or conservatives--I'm not sure what to call them anymore, they are so confused as a group) don't use such pawns, indeed are horrified at such a concept, and while that is a moral victory, it is a huge strategic disadvantage and that is just one reason why they will lose, why they have always ultimately lost, throughout history.
However that is all merely hand waiving. The real reason that the America of the twentieth century will fall in the twenty first century is because American political power has always been for sale, and that massive conflict of interest (people voting themselves a better life) that is the American voting system has gone from rich, white landowners to now literally anyone. And when the mob rules socialism reigns. The last real bastion of the constitutional republic (America is NOT a democracy, not yet, anyhow!) is the Electoral College. It'll never be eliminated by a Constitutional amendment, but it can be neutered by state legislation, and socialist controlled state legislatures are doing a fine job of chipping away at it.
So I hope you are right about the eventual outcome (not about race wars, though!) but I seriously doubt it.
