Donald Trump’s remarks concerning John McCain’s status as a “war hero” elicited much hand-wringing from both his fellow Republicans as well as from Democrats.

However, the truth is that the reasoning that proceeds directly from the premise that someone fought in war to the conclusion that he is a war “hero” is illicit. As for those who for nearly 50 years have been denouncing the Vietnam War as both “immoral” and “unjust,” but who now sing praises to McCain and other ‘Nam vets, matters are even more troublesome.

First, at the peak of the war, Martin Luther King, Jr. exemplified the left’s view when he charged his country with being “the greatest purveyor of violence” in the world because of its actions in Vietnam.

It’s difficult to see how the legions of American soldiers without whom there could’ve been no war can be anything other than war criminals given this assessment of the bloody conflict in ‘Nam.

Second, to avoid this conclusion, many of the war’s critics—like the critics of the wars in Iraq and elsewhere—excuse the “immoral” and “unjust” conduct of the troops by chalking it up to their ignorance or helplessness: The soldiers were “lied to” by their government, they say, or they were “just following orders.”

This line, however, gives rise to new challenges:

Soldiers entering combat jeopardize their lives. They leave their families and loved ones behind, potentially forever. They also consent to take as many lives, to shed as much blood, to destroy as much property, as their commanders deem necessary for victory.

When it comes to a decision as momentous as this, a decision that could come at the cost of everything—including, potentially, one’s own soul—it is the height of recklessness for anyone faced with it to accept the word of another, particularly that of the government.

In other words, all soldiers should exhaust themselves scrutinizing “what they’ve been told,” especially when it is the government that is the source. If at all possible, they should make sure that they aren’t being deceived.

As far as following commands is concerned, this is the old Nuremberg defense. No Commander-in-Chief has the authority to command anyone to act criminally. Such commands, then, are, ultimately, nothing of the sort. Thus, the “I was just following orders” defense is no defense at all, for these are not, and cannot be, legitimate orders.

Soldiers can no more exempt themselves from the charge of wrong-doing by way of appealing to obedience than can mafia hitmen do so.

Tellingly, those who seek to excuse American soldiers who fought in “immoral” and “unjust” wars never think to rely upon these same sorts of arguments when it comes to, say, Nazi soldiers. But if the arguments work in the one case, then they must work in the other. And if they don’t persuade in the one case, then they don’t persuade in the other.

Thirdly, Professor Chris Gazarra, an English instructor and colleague of mine, suggested that it’s possible to distinguish the character of those who participate in a cause from the nature of the cause itself. So, though (say) the Vietnam War is “immoral” and “unjust,” those American soldiers who fought in ‘Nam can still be credited with having conducted themselves heroically and honorably.

This may be a possibility, but, on its face, this position gives rise to multiple paradoxes:

For starters, it implies that eminently virtuous human beings—for heroism and honor belong to the best of the best—can nevertheless be “the greatest purveyors of violence in the world,” criminals responsible for the most vicious of actions.

Moreover, consistency demands that if American soldiers who fight in “immoral” and “unjust” wars nevertheless deserve to be commended for their heroism and honor, then Nazis, Al Qaeda, ISIS, and other non-American soldiers who fight for “immoral” and “unjust” causes could be equally deserving of commendation.

Yet what this in turn suggests is that if Nazi soldiers and Islamic State militants conduct themselves heroically and honorably, then, since bravery and honor aren’t just virtues, but the greatest of virtues, in aiming to kill them, America’s military aims to kill, not the vicious, but the virtuous!

Fourthly, even if we assume that the Vietnam War was morally righteous and just, why assume that those Americans who fought in it are, ipso facto, war heroes?

A hero is a person with the virtue of courage. As Aristotle noted in his classic analysis of courage, a genuinely courageous person, i.e. one who habitually acts courageously and delights in doing so, is neither a person who simply surmounts fear nor, much less, one without fear. Rather, a courageous person acts in spite of his fear, yes. But he is also distinguished on account of his wisdom, for he knows what he should fear and how he should do so.

In contrast, the reckless person, who is not infrequently confused with the courageous person, is ignorant of the proper object of fear. He knows not what he should fear, when he should fear it, and the extent to which he should fear it. The reckless person may act courageously or heroically on occasion—in this regard, he is no different from the cowardly person who is not beyond doing the same—but he is not a courageous person.

If soldiers are simply following orders, or if they are deceived, then they are in a state, not of knowledge, but of ignorance. But knowledge, as Aristotle notes, is a prerequisite of virtue generally, and courage specifically. No knowledge, no virtue.

This is not the final word, but given the prize virtue that is courage, it is worth thinking about.

And by the way: Aristotle served in the military.