Justin Logan, paraphrasing his upcoming paper:

After demonstrating the lack of debate about grand strategy in Washington, we argue that the consensus strategy, primacy, serves the interests of U.S. political leaders, meaning there is little demand for arguments questioning it. Aspiring foreign policy hands would be poorly served professionally if they specialized in a product that their buyers–policymakers–did not want. Accordingly, think tankers and other members of the foreign policy community adopt what we call an “operational mindset”: scholars specialize in relative minutiae, giving support and the veneer of scholarly credibility to whatever foreign policy ideas the policymaker may have, without questioning the objectives themselves.

Rather than a “marketplace of ideas” in which policymakers peruse various policy shops for ideas, the role of the ideas people is mostly to lend scholarly credibility to, and possibly help implement, policymakers’ existing preferences. And policymakers’ existing preferences almost always equate to primacy, partly resulting from the normal bias toward activism among politicians, partly from ignorance, partly from social and other pressures, and partly from the fact that their own incentives point to an expansive grand strategy. In short, there are few restraints and many inducements facing policymakers when it comes to foreign policy.