I don't think that there are many people who will argue, in hindsight, that the Vietnam war was a good idea. There's much that can be said about the history of colonialism in Vietnam, and the oppression of the native people that led to the kind of uprising that feeds so well into communistic regimes. But this is a separate issue from Trump's statements about John McCain's status as a war hero.
I find myself trying to define a war hero during this time period, 2015, compared to the late 1960s and early 1970s, and even earlier from the 1940s and 1950s in the wake of WWII. Defining a war hero in any of those contexts is murky at best. Collinsdictionary.com defines a war hero as "a person who is admired for bravery in war", which is a definition that can be fairly liberally applied. Historically, I think that anyone who served and got any kind of decoration was considered to be a war hero. Many people currently consider anyone who served in the military in or near a combat zone and was discharged honorably to be a war hero. They served their country by following orders, without shirking their duty or refusing to do it.
There are, of course, conflicting opinions on military service and the draft. Several news articles have brought up the question of what was Trump doing while McCain was serving in Vietnam. This brings up several separate lines of thinking to the issue. What of the men who were able to use college as an out from the draft? Or the men who fled to Canada? At the time there were many reasons that a person would not want to go to Vietnam to fight. Not wanting to die is a very good reason ("cowardly" though people may consider it), just as believing that killing other human beings is wrong. But there was also no tangible, imminent threat to Americans. There was no attack on Pearl Harbor, nor a dictatorship pillaging its way across Europe committing atrocious acts of genocide, to incite the need for Americans to shed their own blood for the cause. The "threat" of communism spreading in Asia was the reason for entering this war. Not wanting to fight in that war was not unreasonable. Men who avoided the draft (through legal or "illegal" means) should not be judged harshly for it.
That being said, those who served in the military did
so bravely. It took bravery to go through training, and go out into a
war zone. They followed orders, whether the orders were morally right
or not, and they served their country. That service should not be swept
aside because the President and Congress foolishly ordered them into a conflict.
The news articles that try to undermine Trump's statements by saying that he avoided going to war while McCain went and served are missing the point here. Trump's college attendance and upper class business pursuits are not what is needed to counter his war hero statements. Re-hashing the discussion of the draft and who served and who didn't will not make anyone feel better, nor will it solve any current debates. The issue here is that Trump is praising soldiers who were not taken prisoner during a war, at the expense of those who were. Maybe the point he was trying to get around to was that he didn't think that McCain has done enough to support veterans. That's a point worth discussing. But that's not what he said. No matter how much back-peddling he does now, Trump cannot avoid having conveyed his opinion of POWs, and his perception that they are not as good as soldiers who are not captured and taken prisoner.
I think it's necessary to say that it is not a soldier's fault for being taken prisoner. If a mission goes bad, or an order is given that leads to soldiers being taken prisoner, maybe you can start to have a discussion about culpability around a bad order that led to bad things happening. But that is an incredibly serious charge to make. Especially during the Vietnam war, the North Vietnamese were trying to take as many prisoners as they could to use for bargaining power. This was not a situation where prisoners could only be taken when something very badly went wrong. This was a situation where prisoners were taken fairly regularly, due to no gross errors in judgement. The conditions for the POWs in North Vietnam is described in detail in numerous war memoirs and by the government, and simply surviving those conditions required heroic effort.
I cannot abide anyone who summarily dismisses the experience of a POW and implies that they are not as much of a war hero as a soldier who was not taken prisoner. That kind of perspective displays an inherent lack of knowledge of (first hand or second hand) and interest in the military experience of a service man/woman. While he was trying to say that McCain hasn't done enough for veterans, what he actually said was that he doesn't understand military service and veterans, and he has no interest in doing so.