Matthew Yglesias charts some public opinion data on defense spending that indicates a willingness to pare back the Pentagon. He observes:
"The serious point, politically, would be that on this issue — like many others — politicians actually have an enormous amount of leeway. A decision to pare back the defense budget would meet a lot of criticism, but the public seems perfectly open to it."
I would caution Democrats that any effort to make a headlong charge at the defense budget absent a broader critique of America's international responsibilities is going to run aground fast.
The defense budget is symptomatic of a larger issue - America's international responsibilities and self-described interests around the world. You can attempt to cut the budget all you want (and good luck with that) but doing so in the absence of a coherent and well-articulated strategy to delegate more responsibilities to allies (or a professed willingness to accept more short-term instability in certain regions of the world) is going to look scatter-shot and irresponsible.