It's still in force, despite all the changes in governments. Of course, governments can always refuse, if they wish, and get yelled at, but that's about all that happens.
Shaima's father, though, is a well-known shi'a cleric in Sadr City.
If Pops was the one who killed his divorce-seeking bride, I don't think the well-known cleric/father-in-law would be interested in keeping the murdering son-in-law around.
If the daughter (and we know how daughters don't count quite as much as sons) killed her mother, or had her boyfriend do the dirty work for her, she's hardly a prize for the cousin that they were planning to marry her off to, so I can't see them standing in the way of sending her back home to face justice--and she might prefer to scamper home; she knows nothing of Iraq having grown up in California (she was born in Michigan, but they moved to CA a few years later and she went to San Diego public schools), and I'll bet her language skills are 1st Generation/not-too-nuanced. Even if she speaks enough Arabic to get around, she's dealing with serious culture shock and a sharp abrogation of her freedom (no fiddling around with boyfriends in cars anywhere in Sadr City). It's just not the same.
I have no idea if the husband has any clout with al Malaki (who sent the plane to bring the body home--I kind of think that's because he knew the father of the deceased) but I get the impression that most of the clout is with Shaima's relatives, from what I've read/seen on TV.
Who knows--if the relatives of Shaima get "an idea in their heads," those family members might prefer to take their chances with the US justice system!