German Chancellor Angela Merkel has changed her country’s asylum rules to welcome every Syrian refugee who arrives. Syrians have taken to calling her “Mama Merkel, Mother of the Outcasts.” I wonder what they call the U.S. president.

At many points during the past four years, even relatively small actions might have reduced the pace of civilian casualties in Syria. How hard would it have been to destroy the helicopters dropping barrel bombs on neighborhoods? A number of options well short of major intervention might have reduced the regime’s destructive power and/or strengthened the capabilities of more responsible forces. All were untaken.

This was not some humanitarian problem distant from the center of U.S. interests. It was a crisis at the heart of the Middle East that produced a vacuum of sovereignty that has attracted and empowered some of the worst people in the world. Inaction was a conscious, determined choice on the part of the Obama White House. Secretary of State Hillary Clinton, Defense Secretary Leon Panetta and CIA Director David Petraeus advocated arming favorable proxies. Sunni friends and allies in the region asked, then begged, for U.S. leadership. All were overruled or ignored.

In the process, Syria has become the graveyard of U.S. credibility.