Does the Iraq parliament believe it’s sovereign or not?

Even if it refuses to pass a draft oil law, why don’t Maliki or parliamentary leaders talk about getting it to overrule the 2004 contractor sovereignty regulation imposed from above by the U.S., and then put some Blackwater folks on trial?
That’s why I have never favored the “I support the troops” me-too-ism of some antiwar people. Even if immediately qualified with a statement such as “I support getting them home,” it still seems a no-win proposition. It’s arguing on war supporters’ turf.