The shame should be over the waste of US soldiers lives. If Obama had followed through with military presence, I believe Iraq would be stable. The only way to keep the sectarian violence down is with a strong deterent. I think the extremists could have been marginalized. Now, forget it.
The blood and treasure our nation has offered to 'secure' (i.e. democratize) Iran was not wasted if we learned this lesson.
How much more blood and treasure will be lost before Islam is clearly understood to be a doctrine never ending war?