The reaction of those who fought, and whose friends died, in Iraq has been somber. There wasn’t so much bitter anger as a palpable sadness. Those who thought the invasion was a mistake consoled themselves by blaming President George W. Bush; others blamed President Obama for not fighting harder to keep some U.S. forces in the country after 2011 to try to ensure the lives of the 4,486 Americans who died there didn’t end in vain.

“So many of my friends died in a war that didn’t need to be fought, but that did ultimately provide a reasonable chance for a democratic Iraq in the center of the Middle East,” retired Army officer John Nagl says. “It now appears that all those lives have been squandered because of an unwillingness to pay an insurance premium of a few thousand advisers and some airpower.”