Take a look at the trends here (easy-to-understand chart at the link), again remembering that the data is all in 2010 dollars. In fifty years, we have tripled overall federal revenue, and prior to the current recession/stagnation we had quadrupled it...
Now, let’s put the data in this chart with one showing the rate of spending in inflation-adjusted 2010 dollars:
(chart at link)
While revenues have tripled during this period, federal spending has more than quintupled. The economic expansion of the 1990s (including the dot-com bubble) temporarily raised revenue above the spending trendline, but the slope on spending increased in the early 2000s, and practically launched spaceward in 2007 when Democrats took control of Congress.
I have to ask this: is it even possible to raise taxes high enough to pay for everything the government has promised? I doubt that it is.