Everyone lives happily ever after? They all go to the beach? There's a wedding and everyone does the Chicken Dance?
No such luck, guys.
Birdy's time in Iraq is summed up by the final letter he writes to his uncle (which he says that he won't send). Maybe because it's kind of a downer: Birdy has a lot of conflicting feelings about the war, and many of them are dark.
But they're not all dark. Birdy says he doesn't think we've won the war, but he doesn't think we lost it, either. Or at least, he doesn't believe his squadmates died for nothing:
Because once you have seen a Jonesy or a Pendleton desperately reaching for the highest idea of life, offering themselves up, you don't think about losing or winning so much. You think there is more to life and you go on and you want to find that something more. (15.53)
In the end, Birdy says he understands why his uncle barely talked about Vietnam. When trying to describe war, words don't even begin to cover it.
There's no clear conclusion Birdy reaches in this letter. He's just trying to sort out his own complicated feelings. But for this book, that makes sense. It would be weird if a novel that presented all the complicated details of a war ended with a simplistic conclusion. It just wouldn't fit.
Birdy's story isn't about making a decision about the Iraq War. It's more about helping readers to understand what it was like to be in the middle of it.