Shepherd, another view
Yesterday I noted that the sheep-wolves-sheepdog metaphor implied a shepherd and then pointed out that Chris Kyle was a vocal Christian, defiantly saying he was ready to answer to God for every shot he'd taken.
But you know, it's possible to see Kyle's shepherd as the government.
One of the biggest sins of American Sniper is that Eastwood uses his not inconsiderable skills as a film-maker to lie to his audience about the cause of the Iraq Wars. He leaps from 9/11 to Kyle in battle, leaving aside any discussion of why we were in Iraq and thereby creating the implicature that Iraq was culpable in 9/11. That's a lie. And Eastwood knew it. Any talk about how this film was avoiding politics to focus on a character misses the point: there probably is no way to avoid politics in a film about this war, and if there is, that isn't it. The audience is given Kyle's (probable, certainly in-film) belief as though it were true, told to us not by Kyle but by the omniscient narrator.
A film exploring how Kyle was betrayed by his shepherd the government could have made him into a far more sympathetic character, adding nuance to the third act, when society is tacitly blamed for his inability to reintegrate. And the realization that the shepherd this sheepdog followed so faithfully actually was just chewing him up and spitting him out ... well, that would have been a film worth making.