Via Spencer Ackerman, here's the Pentagon's estimate for future spending. Ignore the gray bars at the top — those are just the numbers for the Iraq and Afghanistan wars. Look instead at the blue bars. That's the base Pentagon budget, and it's increasing 3% per year in nominal terms.
If we applied the same freeze to Pentagon spending that we're applying to domestic spending, their FY13 base budget would be the same as their FY10 base budget: $531 billion. That would be a $51 billion savings in just a single year. So why not do it? What is it that makes us think our national security needs are going to get more and more pressing but not our domestic needs?