From Bob Gates' speech at Notre Dame, on the defense budget and U.S. strategy. The all-important "To Be Sure" graf:
To be sure, a strong military cannot exist without a strong economy underpinning it. At some point fiscal insolvency at home translates into strategic insolvency abroad. As part of America getting its financial house in order, the size of our defense budget must be addressed. That means culling more bureaucratic excess and overhead, taking a hard look at personnel levels and costs, and reexamining missions and capabilities to separate the desirable or optional from the essential. But throughout this process we should keep in mind historian Donald Kagan’s observation that the preservation of peace depends upon those states seeking that goal having both the preponderant power and the will to accept the burdens and responsibilities required to achieve it. And we must not forget what Winston Churchill once said, that “the price of greatness is responsibility…the people of the United States cannot escape world responsibility.”
"Culling more bureaucratic excess" is not a recipe for avoiding "strategic insolvency." The defense budget, including the wars, is $700 billion every year; without the wars, it's around $530-$550 billion. What really is a rigorous approach is to "reexamin[e] missions and capabilities." Simply put, the U.S. has to jettison some things it does abroad. If solvency is the indispensible aspect of U.S. power, then the military needs to look at whether it can afford the "full-spectrum" capabilities it's talked about developing during the latter years of the 2010s. One person's "full-spectrum" is another person's refusal to prioritize roles and missions. Gordon Adams, Chris Preble and the Sustainable Task Force folks are really, really right about this.
You can look at Libya as either a proof or a refutation of the Solvency imperative: it's a new, open-ended commitment for the military and the country; it also places the U.S. in a supporting role. From my perspective, it's more refutation than proof, but it's a reasonably ambiguous case.
Adams, Preble et. al and Gates are not very far apart on this. They'd agree on the outlines for strategy. Maybe they'd debate each marginal case. That's healthy. But typically this debate gets charactured into an annoyingly binary choice between isolation and hegemony, which is a roadmap to slouch toward insolvency.