Total foreign aid for 2012, the most recent year I could find data for, was $37 billion. That's about 3 days of federal spending. We could shut down the military, eliminate NASA, turn off all foreign aid, shut down all of the federal bureaucracy, cut absolutely everything but entitlements, and we are still headed for the cliff.
Start looking and the information is right out there in plain sight. The politicians know it, the economists know it, and while we should know it, we get weeks of "How much air was in the footballs?" instead.
There's only two mathematically significant spending items left. Interest payments on the debt and the major entitlements. Add the Affordable Care Act to this and it just speeds up the date where this happens.
More taxes are no fix to this. You could take 100% of the income of the Fortune 500 companies, every dime from every citizen that makes $250,000 or more, and you don't even pay for a year of this spending, and what do you do the next year? Taxes at any sustainable rate, whatever sort of "Tax the Rich Until They Squeal!" program you envision, do not touch this curve.
We will cut these programs. Sooner or later, we will have no choice. The only question is do we do it in some controlled fashion that moderates the impact or do we continue on the current spending path and wait to see what the collapse looks like?