DESPITE MYRIAD hearings, investigations and prominent trials of privates and specialists, no commissioned officer has received serious punishment for any of the many confirmed cases of prisoner mistreatment in Iraq, Afghanistan or Guantanamo Bay, Cuba. Two of those involved in the Abu Ghraib scandal have received letters of reprimand. One was demoted. None has been court-martialed.

By contrast, Gen. Kevin P. Byrnes, 55, a four-star general who served 36 years in the Army, was abruptly relieved of his command on Tuesday. According to his attorney, Gen. Byrnes, who is now divorced, stands accused of having had an extramarital affair with a civilian who is not his colleague, is not his subordinate and has no connection to the military. An officer familiar with the case told The Post that despite the apparent irrelevance of the affair, the harsh verdict -- apparently the only such demotion of a four-star general in modern times -- was justified: "We all swear to serve by the highest ideals, and no matter what rank, when you violate them, you are dealt with appropriately."

From this incident, it is possible to draw only one conclusion: It's okay for officers to oversee units that torture civilians and thereby damage the reputation of the United States around the world, do terrible harm to the ideological war on terrorism and inspire more Iraqis to become insurgents. Having an affair with a civilian, on the other hand, is completely unacceptable and will end your career.

It's true, of course, that we don't know all the details of this case, and it is possible that some aspect of it will justify the dismissal of Gen. Byrnes. But if there is a justification, it had better involve national security at the very highest level. As it stands, the case reminds us of nothing so much as Voltaire's paraphrase of a British justification for the pointless execution of an admiral in the 18th century: "In this country it is found requisite, now and then, to put an admiral to death, in order to encourage the others to fight."