While supporting basic science research is indeed essential for protecting national security, can that be our sole primary motivation for pursuing knowledge of the natural world? When asked by Congress whether Fermilab, the expensive atomic accelerator, would contribute to the national defense, its founding director replied that the contribution would be "… not to the defense of the nation, but rather to what made the nation worth defending."
This session is very timely -- for NASA and EPA, too. In government, it seems that they're really pulling away from having scientists on the payroll (not as contractors) who do basic research that may not have an immediate practical use.
Sean Carroll, a Physicist at the University of Chicago, recently posted on why do we do science that isn't immediately practical (look back in his archives and you'll see more discussion of this).