Here Trump has considerable leverage. As the Military Times observes, there is no American custom of senior military officers resigning in protest over morally objectionable, yet ostensibly lawful, presidential orders. Further, the Manual for Courts-Martial states that “the dictates of a person’s conscience, religion, or personal philosophy cannot justify or excuse the disobedience of an otherwise lawful order.” As Christopher Fonzone observes in Just Security: “Commentators should not expect military disobedience to save the nation from simply unwise or legally contested orders.”
By nature and circumstance, Trump presents the prospect of more such orders. He is trailing in the polls; as November draws near, he may be increasingly desperate to prevent defeat by misusing his power as commander-in-chief.
Possibilities abound. Suppose, for example, Trump invokes the Insurrection Act to deploy active duty troops on the pretext of preventing disorder in a restive city. Or, perhaps, dispatches soldiers to polling places in heavily African-American precincts—claiming that he is acting to protect voters from prospective violence but, in truth, to discourage them from voting…
Only a resignation in protest has any chance of provoking an adverse public reaction. What is more likely to do so is something without precedent in American history: a concerted refusal by senior commanders to obey a presidential order.