It didn’t have to be this way. Our friends did not have to be left out in the cold to seek Iranian protection. Three years and a won war had given Obama the opportunity to establish a lasting strategic alliance with the Arab world’s second most important power.

He failed, though he hardly tried very hard. The excuse is Iraqi refusal to grant legal immunity to U.S. forces. But the Bush administration encountered the same problem and overcame it. Obama had little desire to. Indeed, he portrays the evacuation as a success, the fulfillment of a campaign promise.

But surely the obligation to defend the security and the interests of the nation supersede personal vindication. Obama opposed the war, but when he became commander in chief the terrible price had already been paid in blood and treasure. His obligation was to make something of that sacrifice, to secure the strategic gains that sacrifice had already achieved. …

Years from now, we will be asking not “Who lost Iraq?” — that already is clear — but “Why?”