Of course, to be fair it likely didn't help that the current administration decided to yank nearly all US troops out of the country before the job was done, either.
No matter your feelings or opinions on how the war began or was handled during the Bush administration, you cannot deny that finishing it properly should have been a top priority no matter who started it. Consider, if the allies had withdrawn from Germany that soon after WWII, the Nazis (or a derivative group thereof) would have arisen once more, and Germany would likely still be a mess today. Instead, post-WWII the allies (for better or worse) kept occupation for years on end, slowly passing control, then autonomy, then self-defense, etc to the post-war German government ( well, governments, as we did have two of them for the longest time thanks to the USSR.)
Why this wasn't done properly in Iraq is a serious head-scratcher, especially given that Iraq was indeed an artificial country (thanks, England!), and doubly so because of the regional culture plus pre-existing secular tensions. It would have been a long, expensive road, but it was certainly at least doable.
Incidentally, it probably didn't help that Syria went straight to hell in recent years, either - or that Iran has been working like hell behind the scenes to keep things unstable. But to be honest, those only serve as stronger arguments for keeping treasure and troops committed towards reconstruction in Iraq (and maybe a bit of that towards keeping Iran's little activities clamped down as hard as possible).
Long story short: anyone who tries to place the blame for the mess on any one person or political party is an idiot. There's plenty of blame to go around on this one...