Oh, 'coz no one in Washington EVER tries to spin a shit sandwich into something that looks like ham.

As has been pointed out, this outcome was not unforeseen. Only ignored by those in charge when it might have made a difference – which was before we invaded. Warning after warning after warning was issued:
Warning after Warning
Some of us knew this and always said the invasion of Iraq was a mistake of historic proportions. We were called traitors at the time.
The U.S.-Iraq Status of Forces Agreement signed between Bush 43 and Nuri al-Malaki on June 13, 2008, REQUIRED that all US Forces would be out of Iraq by no later than December 31, 2011. So what choice, again, did President Obama have about leaving troops in Iraq past that date? He did try to negotiate leaving a force. Al-Malaki and his government refused.
Status of Forces Agreement History
And yes, the senseless loss of all those lives makes me sick.
The only smart thing would have been to never invaded in the first place. That’s why 41 stopped short of Baghdad.
Remember Colin Powell saying, “You break it, you buy it?” Well, guess what? We done bought it.