Donald Trump has certainly given all of us many reasons for concern about the possibility that he could become president, but I would like to offer my perspective, based in part on my past experience as an officer in the Army.

Where to begin! As a longtime admirer of John McCain, I suppose the Trump outrage that most sticks in my craw, at least from an emotional standpoint, is his contemptuous dismissal of McCain’s heroism as a POW and, more generally, of the sacrifices made by every other POW in every one of our wars. (“I like people that weren’t captured,” Trump tells us.)

This from a guy who (legally, of course) worked the system to avoid the draft and avoid serving in Vietnam, but who pats himself on the back because he also avoided sexually transmitted diseases while he was sleeping around in New York (or so he boasts), while others of us were risking their lives in combat. “It is my personal Vietnam. I feel like a great and very brave soldier,” he bragged.

I suspect that my classmates and comrades who died and were grievously wounded in Vietnam would not necessarily be all that impressed with what Trump describes as his bravery.

They might also not be impressed by his very recent comment that he “always wanted (wanted!) to get the Purple Heart; this was much easier,” when he was handed a real veteran’s medal at a campaign event. Does he even begin to understand that the Purple Heart is awarded only to men and women who are killed or wounded in combat? That only a fool would want to win the Purple Heart?

Our heroic almost-soldier also claims that because his parents sent him to an expensive military-themed prep school, he received “more training militarily than a lot of the guys that go into the military.” Which no doubt explains Trump’s absolute knowledge that “our military is a disaster” and his boast that “I know more about ISIS than the generals do, believe me!” How could we not believe him, given all that training and experience that he got in high school?

And, of course, we should not overlook the great sacrifices that Trump says he has made for his country. In particular, he specifically compared his building of wealth (he “worked very, very hard” building some buildings and bankrupting others) as “sacrifices” that he claimed were particularly comparable to the ultimate sacrifice made by Capt. Humayun Khan in Iraq, not to mention the more than 7,000 other Americans who were killed there and in Afghanistan, the 58,209 Americans killed in Vietnam (the war Trump was too busy to attend) and the hundreds of thousands of Americans killed in other wars. And it would probably be impolite to mention the sacrifices made by thousands and thousands of wounded veterans still surviving those wars.

Is it fair to ask whether our Donald has a sense of proportion, or even common sense, when he tries to equate his “sacrifice” to those of these brave warriors and their Gold Star families?

I suppose that all of my observations will be dismissed by Trump’s defenders as mere quibbles. After all, we are told, we should ignore what he actually says and admire him because he tells us what he really thinks, even when what he says isn’t particularly coherent. And these little teeny gaffes aren’t all that important anyway, right? What’s important is that he’ll shake up the status quo and not be hobbled by “political correctness” (whatever that term is actually supposed to mean).

Should we truly be reassured by such arguments? Well, maybe not.

When Trump has vowed (repeatedly) that he will order members of the armed forces to commit war crimes – to torture suspected enemy combatants and kill their families – are we supposed to dismiss it as idle talk? That it’s just Donald being politically incorrect?

When he has essentially declared war on more than a billion Muslims – 23 percent or so of the world’s population – should we just dismiss it as good old Trump being Trump? Or maybe we should credit the judgment of people who actually know about national security issues, such as Gen. David Petraeus and many others, who have concluded that such inflammatory, bigoted, anti-Muslim rhetoric is not only toxic and counterproductive, it is a serious threat to our national security.

When he has slandered the members of an entire national group as being unworthy – as drug dealers, rapists and murderers – and has asserted, in effect, that Americans whose parents were born in Mexico aren’t true Americans, should we believe that this is the kind of person we can entrust with the conduct of this country’s foreign affairs?

Trump has demonstrated time and time again that he is unqualified to be president and commander in chief of our armed forces. He has demonstrated time and time again that he does not have the character, temperament, self-control, maturity, knowledge or judgment to be trusted with nuclear codes or any decisions of war and peace.

The exceedingly frightening Cuban Missile Crisis, which posed a very serious threat of nuclear war, occurred when I was a newly minted second lieutenant. My memory of the crisis is vivid, because our unit was placed on high alert and we thought we might be going to war any minute.

As a result of President Kennedy’s steady hand on the tiller, nuclear war was averted. The thought that someone like Donald J. Trump could have been in charge of life and death decisions in such a potentially catastrophic situation is absolutely terrifying.

(Don Burns, a 1962 graduate of West Point, was an Army Ranger and paratrooper who served on the Czech-German border during the Cold War and in combat operations in Vietnam.)