Here's what Jonathan Stevenson has to say in the May Harper's in a report called "Owned by the Army: Has the president lost control of his generals?" [emphasis in the quoted material is mine]
The armed forces have become an insular professional class. At the same time, the United States has moved toward a quasi-imperial – or to use the Niall Ferguson's more tantalizing term, "crypto-imperial" – model of security, whereby open-ended military deployments keep the homeland safe by effectively pushing its borders outward. This is what turns generals into proconsels, especially when their areas of responsibility are, as Central Command's have been for a decade, theaters of war. Foreign governments view regional commanders as the principal representatives of the United States, and their military exploits and media prominence of for them greater visibility authority than their civilian counterparts in the State Department, which is roughly one-fourteenth the Pentagon's budget and one-third the personnel. . . . The ramifications are clear: presidents with decreasing military experience direct regional combatant commanders newly emboldened to second-guess civilians on strategic matters.
In this light, and inclination on the part of some senior military officers toward seizing a greater share of putatively civilian authority is not surprising. In a recent issue of Joint Force Quarterly, a Pentagon-sponsored military magazine, Lieutenant Colonel Andrew Millburn contends that a military officer's oath and code of ethics accord him the "moral autonomy" to disobey an order he believes would harm the United States, its military, or the soldiers in his charge "in a manner not clearly outweighed by its likely benefits." Millburn's argument conjures the image of a troubled German soldier refusing to execute a Jewish prisoner, or a noble G.I. disobeying Lieutenant Calley's order to massacre Vietnamese families at My Lai. Millburn, however, quickly turns the argument from "the obligation to disobey an illegal order" on the tactical level to "the strategic level of decision-making," at which he believes the soldiers judgment "provides a healthy check in the execution of policy." Millburn ultimately imagines a dialogue of equals between civilians and soldiers, playing into entrenched post-Vietnam truth-to-power fantasies.
. . . Absent an outright traitor or psychopath in the Oval Office, though, a government takeover of the tanks-at-the-White-House sort seems far-fetched. The more likely result, and the one suggested here, is a coup d'spirit, in which civilian leadership voluntarily submits to the military way of thinking. The risk that this state of affairs poses to the country is considerable: soldiers' essential expertise is not in grand strategy but in the operational art of warfare. If they are left to determine the United States is strategic and diplomatic direction, they will tend to do so on the basis of the feasibility of their operational missions are, worse, on the perceived need to develop the operational capability of fulfilling future missions – another hazard of an open-ended war.If you could read this stuff without a sense of real chilling fear, then you must not know about or know enough about the continual history of the military in all ages and climes overthrowing the constitutional or legitimate authority. Let your mind mull a little bit what the phrase "moral autonomy" purports in this context, for example.
But I agree with the insight that posits a surrender of civilian independent thinking to a subservient sort of approach to the "expertise" that resides, supposedly, in the military leadership. You can already see this at work in our society. The idea that four-star generals have to be summoned before congressional committees to expound on policy matters is anathema to what the Founders had in mind. But, of course, those among us who actually know what the founders had in mind are few; those among us who believe they know what the Founders had in mind are legion – and incorrect ninety-nine percent of the time.