It’s interesting to me that “must” is so big in the tag clouds of both the Bush and Obama NSS. “Must” implies a lack of freedom; it’s much different than “may” or “can.” It seems odd that the world’s sole superpower, hegemon, unipolar state etc. thinks strategically in terms of “must” rather than “can”. Recall your Thucydides:
The strong do what they can and the weak suffer what they must.
The logic is quite clear; the powerful have freedom to pursue whatever ends they wish, while the weak are constrained by the whims of the strong. Both NSSs, however, use the language of constraint rather than the language of freedom. The most powerful state that the world has ever known feels deeply constrained by the exigencies of the international system.
One response to this would be that “must” is there simply for political effect, and is intended simply to foreclose alternatives that “may” or “can” would leave open. I think that there’s considerable truth to this, but I don’t think it’s the whole story. Rather, I suspect that both the policymakers in the Bush and the Obama regime feel the artificial, self-imposed constraint of “must” as a genuine imperative. I suspect that psychologically, institutionally, and politically the imperative of “must” becomes real for policymakers, such that even the most powerful actors in the most powerful state that the world has ever known subjectively “suffer what they must,” rather than “do what they can.” It’s worth noting that the above quote was part of the patient Athenian explanation that they had no choice but to burn Melos to the ground and put its inhabitants to the sword.
I find this a bit of a scary thought.