21st Century Science - Who's Paying the Bills?

As the balancing the budget becomes a hot political issue for the 2008 Presidential campaign, one has to wonder how many more cuts can science take?

The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 "to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense…" With an annual budget of about $5.92 billion, we are the funding source for approximately 20 percent of all federally supported basic research conducted by America's colleges and universities. In many fields such as mathematics, computer science and the social sciences, NSF is the major source of federal backing.
http://www.nsf.gov/about/glance.jsp

I'm not trying to make a political statement here, what I want to point out is how little we truly spend on science, unless it's related to the military or corporate R&D.
Our interest payments on our national debt are 10x our expenditure on science, space, and technology. Does anybody care anymore? Or is it time for U.S. scientists to emigrate to Europe, where apparently their budget is 78 billion U.S. dollars (58 billion euros)?

http://www.theregister.co.uk/2006/11/30/europes_research_budget/

At what point do we start worrying about a brain drain and should there be concerns that the EU's scientific budget is more than 3x the U.S.?