Kerry believed that by protesting the war upon his return he could get the attention of Congress and bring an end to the war sooner, thus saving many American lives.

That's pretty common knowledge now, and whether you believe as he does is irrelevant to the conversation. I cited him as an example of someone that stands by his beliefs and convictions yet many abhor him for those beliefs even though they may admire bush for standing by his ill beliefs.
_________________________
Tent makers for Christie, 2016.