The United States already has about a billion firearms — and in recent weeks, there has been a surge in both assault weapon sales and paranoid anti-government rhetoric. It makes sense, then, that people are beginning to worry about the possibility of an insurrection in the United States. If that happens, it is not likely to occur in winter, or indeed this year, but it seems there is a chance of something of the sort occurring in the next five years. If you want an idea of what an armed rebellion would look like, the current rebellion in Mali is probably the best example to consider. The rebel army is fanatical, poorly disciplined, and not in the best of health. It holds a view of the world not shared with anyone. Yet it imagines itself a combat-ready army and the voice of the people. This makes for a particularly grisly setup, leading to large numbers of civilian casualties when the rebel army runs unopposed, and rebel casualties in the hundreds when the rebel army comes across any real army.
There are several reasons to think this could happen in the United States too. The fanatical militia groups who would be at the heart of such a rebellion have existed for a generation and now may number close to 1 million (though no one should imagine that a majority of them would ever work together on anything). Rebels in the United States could gain covert financial support from narco-rebels in neighboring Mexico. It is not just the militia members who overestimate their popular support; some of their friends in political office also imagine that there is some popular appeal for overthrowing American democracy and installing an essentially foreign culture by force. With the decline of television, newspapers, magazines, radio, and other mass media, the common assumptions of collective American culture are breaking down, making it possible for extremist groups to imagine that their views are widely held. There is reason to fear groups that are well-armed and extremely overconfident. They can do a lot of damage in a short time.
From the outside, it is hard to imagine what the Mali rebels are thinking as they march forward to near-certain death. If there is a similar insurrection in the United States, it will not make any more sense than this.