The military is fessing up about a bad shooting in Iraq a little while back:
The American military admitted Sunday night that a platoon of soldiers raked a car of innocent Iraqi civilians with hundreds of rounds of gunfire and that the military then issued a news release larded with misstatements, asserting that the victims were criminals who had fired on the troops.
The thing you need to remember when you hear this kind of story of misconduct is that literally hundreds of thousands of foreign personnel have served in Iraq since the invasion in 2003. In that context, it really and truly is just a small handfull of bad apples who've done this kind of thing while the overwhelming majority have exhibited exemplary conduct by historical wartime standards.
But by the same token, what you see is that when such a massive undertaking goes on for years and years then even in a military where the overwhelming majority are well-behaved, a certain number of terrible things happen. And that is why Iraqis, quite rightly, don't want to see a foreign military operating on their soil and not subject to their laws. No sensible country would want to see such a thing happen, precisely because even under the best case it's still going to lead to the occasional tragedy. And of course the Defense Department, also quite rightly, has no intention of letting American military personnel engage in active operations on Iraqi soil while subject to Iraqi criminal jurisdiction rather than to American military law. Which is precisely why it makes sense for both countries for us to begin the process of packing up and leaving. Completely apart from the quality of the troops' performance (generally very high) or the quality of their tactical missions (seemingly very high recently) the overall situation is inherently untenable.
DoD photo by Senior Airman Julianne Showalter, U.S. Air Force