That three strikes Purple Heart rule.

Sam Schechner, writing in Slate, answers the pressing question: How do you get a Purple Heart anyway? Citing various military texts, he paraphrases: "a Band-Aid boo-boo is fair game, so long as enemy action is somewhere obvious in the causal chain." He concludes with the Slate "Explainer" sign-off: "Next question?"

Okay, I have a question. If it is so easy to get a Purple Heart, how was the military able to have that rule allowing you to go home early upon winning three? Three "Band-Aid boo-boos" and you can go home? How did that work exactly? How many people left early that way? How eagerly did people write up scratches in the hope of escape? As I write that, I worry that I'm insulting the people who went to war and did their duty and did not look for an out. But is that not what Kerry did? I don't particularly blame him, because virtually all the young men I knew--I went to college in 1969-1973--openly and on a day-to-day basis looked for ways to avoid Vietnam.

Did the three Purple Hearts rule work because when you were in action, fighting with a group of men, peer pressure would keep you from pursuing that out? If so, and if Kerry overcame the pressure and took the out, then the Swift Boat Vets are the peers returning to express the very anger that those swayed by peer pressure strive to avoid.