Often, economic crises are caused by real physical problems - like draught, war, demography, or technological innovation that robs one economy of a competitive advantage over another.

Other times, economic crises result when asset bubbles burst, or financial markets collapse. That was the case of the Great Depression - and more recently the Great Recession.

The economic crisis of the moment - the "fiscal cliff" - does not result from any of these factors. In fact it is not a real "economic crisis" at all, except that it could inflict serious economic hardship on many Americans and could drive the economy back into recession.

The "fiscal cliff" is a politically manufactured crisis. It was original concocted by the Republican Senate Leader, Mitch McConnell as a way to get past the last crisis manufactured by the Republicans - the 2011 standoff over increasing the Federal Debt Ceiling.