Current trends... the rise in immigration (we've added over 100 million to our population is the last 50 years) will swamp us and multiculturism will lead to balkanization (if you teach an african, an arab, chinese, etc. that his culture is equal to or better than ours, why should he assimilate?).
Small number of rich elite running a totalitarian welfare state?... heck, thats what we've got now. You've got to be rich or politically connected to have much chance of winning all but the most local of political offices and the system is so rotten that the few honest people who get in are corrupted. Gov't growth is leaving the realm of geometric growth and is becoming exponential. History teaches that when you concentrate that much power in gov't hands, you pay the price.
On the bright side, a person interested in history (as I am) should be very entertained by observing how the first empire of the nuclear age falls into ruin. Rosy future or grim one, we're in for some interesting times.