I guess the US is not "broke" because of the capacity to tax the productive at even higher rates?
It's not that there is no more money in the economy. It's that the taxpayers no longer have the stomach for increased taxes and spending. This idea that wealth exists to be taxed to feed an insatiable government bureaucracy is ludicrous. Wealth is property, plain and simple. It belongs to those who have earned it, not to the government. Consequently, government should request no more than it needs to meet Constitutional or socially agreed to obligations. Government doesn't see it that way.
Apparently, neither does Michael Moore.