Some 15 million Americans are unemployed under the narrow terms popularly used. Under other terms used by the Bureau of Labor Statistics, the real unemployment rate is more like 17 percent, over 25 million people. So it's near certain that at least 40 million households, or over 150 million people, face dire income issues -- little to no regular income, or income that just barely meets living expenses. If there is any cushion against this, it is the fact that most households now have more than one income-earner (but many of those really need two income-earners).
One way or another, it is more than reasonable to conclude that on the order of one half of the US population feels financially insecure. Add to that the fact that most Americans know that they have unstable access to health care, given that most health insurers enthusiastically embrace yanking care away when it is needed. Add also the government fiscal crises, so education, infrastructure and other essentials are threatened. We sustained this instability for years with the credit bubble. (The bubble was 'load-bearing.') Now that has collapsed and will likely stay collapsed, despite Obama efforts to re-inflate the bubble.
What do most Americans have reason to feel safe about? In a country where the general population was less apathetic and less indoctrinated in acceptance of and obedience to authority, government and private elites might well be worrying about social upheaval.