Friction in this relationship, historically, is not unusual. But in recent days, and for the second time in Trump’s term, it has raised a prospect of high-level resignations and the risk of lasting damage to the military’s reputation.

Calm may return, both in the crisis over Floyd’s death and in Pentagon leaders’ angst over Trump’s threats to use federal troops to put down protesters. But it could leave a residue of resentment and unease about this president’s approach to the military, whose leaders welcome his push for bigger budgets but chafe at being seen as political tools.

The nub of the problem is that Trump sees no constraint on his authority to use what he calls the “unlimited power” of the military even against U.S. citizens if he believes it necessary. Military leaders generally take a far different view. They believe that active-duty troops, trained to hunt and kill an enemy, should be used to enforce the law only in the most extreme emergency, such as an attempted actual rebellion. That limit exists, they argue, to keep the public’s trust.