I'm reading a fascinating book on the fall of the Roman empire, a topic I've had an interest in for a long time. It amazes me that such a mighty and expansive civilization could collapse, and makes me wonder about any parallels to our country/empire.
I'm only about about half way through the book, but so far it seems that everything can be neatly summed up by saying that the expenses of the empire ramped continuously into the fourth century AD to completely unsustainable levels, primarily due to military spending and welfare. Eventually the tax burden became so great that working classes became destitute and devolved into destitution and lawlessness.
In other news, US tax revenues are down 28% year over year in March, and Obama and crew plan to spend record amounts of money while saying they're going to cut the deficit. Meanwhile, back on planet Earth, the United States Treasury is running on fumes.
In all fairness, though, the Roman Empire didn't have a fractional reserve monetary system which means that they were unable to borrow to pay expenses. Balanced budget all the time. However, this means that our eventual implosion will be much quicker and more dramatic when it arrives as almost all funding will be cut instantaneously when we default. It could literally happen in the course of a year or two.