No I don't think that is likely, the unrest we see today is nothing compared to what this nation has weathered in the past.
All you have to do is review some history, the Civil War for example, even the 60s, with JFK, RFK and MLK being assassinated and all the riots and issues going on then... those times make these times look mild in comparison.
But what America does face is a redistribution of wealth, out of the country and to other nations... as China, Mexico, Brazil, etc. become more equal as nations to our own economically, our ways of life will become more moderate (less physical wealth, less of our society with two, three, houses, etc.).
What we need to fear, if anything, is a collapse of our economy... an occurance worse than what we dealth with in 2007... if that were to occur in the next few years I doubt we would truly recover from it during my lifetime, and typically the only thing that pulls a nation out of such a collapse is a very costly, very deadly war.
We as a nation are oblivious to our 20 Trillion dollar debt... but eventually running up our debt, while having a yearly trade deficit running around a trillion dollars (all nations combined) will be prove to be unsustainable... and then the life styles we have grown accustomed to will be but a memory.