Maybe a reason some people are praising the actors' performance highly but not recommending to see the movie is because the actual experience of watching "In the Valley of Elah" is just too unsettling, like a mirror of our actual experience in Iraq (whatever your political views may be).
Notice that although the movie's crime story is solved by the end, it turns out not to involve any conspiracy, the exact reverse of what the story has led us to anticipate (we misread the army official's behavior, assuming the military must be trying to cover up something). We're pulled into the whodunit but we don't get the satisfying twist that crime stories like this usually give us. The young soldier wasn't killed while heroically trying to uncover a dark secret. Instead he dies senselessly and for nothing.
But isn't this experience, this let down while watching the movie, a lot like our real life experience of the past 4 years? We wanted to believe Iraq was somehow linked to the terrible crime inflicted on us, but our early hoped for retribution has instead come up against a completely different reality: no weapons of mass destruction, and a lengthening war no one wants. The David of our hopes marched into Iraq, but the lengthening shadow of Goliath still stands before us.
Terrific movie. Works on so many levels at once, never preachy, never obvious, completely real. I didn't leave the theater feeling great but I felt fully engaged, and I felt like it mattered again to be an American. The people in this movie are, almost every single one, so likable (at least sooner or later they are), and the places are so recognizably American in ways I care about that the movie was an affirmation. Except, of course, the people in this movie - like all of us - are trapped in a war with awful unforeseen consequences, hitting where we live, even if the bombs don't. So the would-be affirmation leads only to sad disappointment and remorse, the more heartfelt for its real-life applicability.
In the movie it's pretty clear that Mike Deerfield is destroyed exactly because he starts out as such a good and decent young man. Besides being brave (getting out of the Humvee to take the photo), he has a heart and a conscience, and therefore couldn't rationalize away his part in killing the Iraqi boy, no matter how unintended. In one sense, Mike tries to be like a David who faces the monster Goliath of war.
But that's the conventional view. The much more disturbing one is that Mike's downfall is rooted in the fact that he himself has become a monster, no matter how unintended. And, sadly, isn't Mike really a stand in for us? In the Valley of Elah the roles have been reversed and America has become the bad guy in some crazy unintended way. Notice that America is clearly the Goliath in power compared to a bunch of rag-tag Iraqis, no matter how murderous some of their intent. Yet we are felled by a small Iraqi boy's fearless stand (why didn't he just run out of the road?!), the boy's implied recrimination shooting for Goliath's heart instead of his head - no less deadly for that.
A fine and decent people are brought low, their best motives twisted around and perverted until they find themselves inflicting barbarity they never thought was possible, just like the father in the movie who can't believe until the end that his son's comrades could be culpable. That's why the father hangs the US flag up-side-down, making the universal distress call: something's gone seriously wrong and we need any help we can find to get out of our Valley of Elah.
The powerful thing about this movie is that we are propelled seamlessly if uncomfortably back and forth across these two understandings of who is David and who is Goliath. The reverberations continue for a long time.