“Get back to business!” With this tweet, President Trump directed his secretary of the Navy, Richard Spencer, to stop the naval officers charged with oversight of the SEALs from disciplining one of their own. That order was confirmed on Monday by Defense Secretary Mark Esper, and over the weekend, Mr. Spencer was fired.

There are three problems with Mr. Trump’s action. The first is that it is very much the Navy’s business — and every military’s business — to maintain, as the military so often recites and Mr. Spencer put it in his final letter to the president, “good order and discipline.” In conducting their “business,” our military services are not and must not be commanded in support of political ends, as Mr. Trump was apparently doing here.

How the president chooses to value order and discipline in his White House, and if at all, is of real concern to all Americans. But the military is not an extension of his White House. Some may argue that all actions by a president may have some political component, yet instead of constraining that component, this action by this president celebrates and encourages it.

The second problem intensifies the first. Contamination from the president’s approach is amplified when his judgment is largely shaped by television commentators and his decision announced by tweet. The military has well-established procedures for assuring good order and discipline. They begin by eliciting a judgment by peers. No one is as well positioned to balance the exigencies of combat and the demands of law and ethics as a panel of fellow sailors, Marines, airmen or soldiers.