The weirdass thing is what happens in 16 days.
Parts of the US government are still functioning. These are mostly parts that are pre-funded, like the military and so on.
Obamacare is still rolling out because the legislation that put it through defined it as an entitlement, so its funding works the same as food stamps.
However in 16 days the US government debt hits the debt ceiling, and then the practice of borrowing more money to pay down the debt becomes illegal. The Republican-led House is demanding even more concessions to allow the debt ceiling to be increased yet again.
So what happens in 16 days if the US government can't borrow money anymore? Does Obama call up the Treasury and say "OK, guys, get the printers rolling, we're now Nazi Germany in 1944. Time to print money."
We've already been printing to the tune of $80B a month buying Treasuries (Thanks Bernanke!).
Inflation is already under way.
But you make a great point, the limit is nigh.
With Congress in stalemate over Obamacare and the budget, what'll happen if/when the US goes into bill-lock?