Before college John Kerry opposed the war in Vietnam.
When John Kerry could not obtain a deferment to study in France, he enlisted in the Navy Reserves, from which he went to Vietnam.
When he got back he found that his carefully accumulated medals didn't do him much good politically in a place like Massachusetts. And it happens that for whatever reason, John Kerry went whole hog into the antiwar movement.
Now it's 3 decades later and he wants to present himself as a war hero. Will the real John Kerry please stand up? Can we determine which one is the real one?
Well, one metric is whether he ever broke the faith with his former comrades beyond switching sides.
He certainly broke faith with his Vietnam buddies, accusing them and even himself of outrageous atrocities. To my knowledge neither he nor any he accused ever suffered any personal consequences beyond bad PR for Vietnam veterans, but that was plenty IMO. (Branded as "baby-killers", I wonder how many of them redeemed themselves to the Left by becoming abortionists?)
What about his antiwar buddies? For instance, did he go running to the feds when people from his organization, Vietnam Veterans Against the War, proposed killing pro-war Senators? Why heavens, he wasn't at any such meeting! Until contradicted by FBI surveillance information, that is. Then, like cornered Democrats always do, he wanted to "move on".
So he told authorities about events that might not have happened to the detriment of the war buddies he's trying to get support from now. But when he had information that people were proposing assassination of pro-war Senators, he didn't go to authorities, and he tried to hide that fact until he was busted.
In short, he kept the faith with the antiwar people, but not with his fellow veterans. In the presence of innumerable flip-flops, that may be the closest thing to sincerity that we ever see from John Kerry.