Yay. So, my theory that I believe is the most real, is Hyperinflation. Hyperinflation is where the Value of the dollar becomes zilch. And we sowed the seeds of this possible hyperinflation when the government started spending out of control. We owe Billions to China, etc. The more we owe, the more the countries we owe want to collect. By the turn of the Century, Federal Spending was nuts. The debt and deficit problem was insurmountable. Debt and deficit will compound at a frightening rate, as it already has. The White House just ignored it back in 2008. The debt is piling up right now at a rate of Nine Billion a Day, or Fifteen thousand a second. Sound scary? And it will keep growing. And even though the stock is doing good, we would still be in massive debt, to the point that Europe and China would declare a full scale default on the US Treasuries. The value of the dollar will plummet, as nobody would want to stay with the risky US Dollars, switching out for sturdier currency. To help finance the growing debt, the Federal Reserve begins Monetizing larger portions of the Debt, and the printing presses run around the clock printing money. Money that has little to no value. Cut to the chase here. The Stock Crashes, people get laid off, riots happen, and cities are burning down. Chaos. It makes the Great Depression look like a piece of cake. The national Guard attempts to stop some riots, but half of their men are gone. Army Reserves are laughably low as well. People who are prepared for this sort of thing dig in to defend. Law is pretty much gone, power is gone, trade is gone, prisons are gone. Cut forward to four or five years into this "Downfall" Europe, and the UN sends in the Towtruck, retaking key areas from the hostiles in the area. Then, in an effort to keep the Lawless Brigands that roam the country from killing more, they pass a Law preventing many guns from being used. The only problem is, the Lawless are just that. Lawless. They wouldn't do it, and the people that survived with their guns know that. They refuse, and the UN comes in by force, forcing them to comply. Many Militias would fight back, especially in areas of Idaho, Arizona, Etc. They would retake Texas first, for oil to power their APC's and Tanks. I am unsure of who would win. It would be very bloody. Technically, as the U.S. dollar effects much of the world, this could be considered a world war of the UN got involved. Anyway, I think too much.
That's right. In the end, Civil War 2, would be raged over gun laws. There practically is one right now over gun laws.
First, we don't owe as much to china (or any country) as you think. Most of the debt owed to anyone is actually in the states. The government "borrows" money from people, and don't pay it off, so the interest just stacks up. On top of that, our national deficit is decreasing. We may be alive to see America actually making money.