But Obama and the aides who continue to defend his policy are right about one big thing: There were no easy answers in Syria. When Assad began killing his fellow Syrians to put down a rebellion, the United States had no clear way of stopping him, absent another potentially catastrophic Middle Eastern war. Obama’s approach to Syria failed, yet any alternate approach may have failed as well.

Yesterday, President Trump put his own stamp on Syria policy, and it was not encouraging. Against the advice of his advisers — and, in some cases, to their surprise — Trump will pull out the remaining 2,000 American troops within 30 days.

As part of the announcement, Trump claimed victory, saying that the extremist Islamic State had been defeated. And he can fairly take credit for overseeing military victories against it. But many experts believe that an American withdrawal may now allow the Islamic State to regain some of the central Syrian regions it once controlled.

Only nine days ago, Brett McGurk, who helps lead Syria policy under Trump, suggested a pullout would be “reckless.” In September, Defense Secretary Jim Mattis similarly suggested that “blindly” deciding to leave would be a mistake. And yesterday a couple of high-profile Republicans in Congress blasted the move.

For all of their differences, both Trump and Obama have shown a welcome reluctance to risk American lives for an uncertain — or nonexistent — benefit. But that reluctance still needs to be paired with a strategic vision. In Syria, and most everywhere else, Trump seems to lack that vision.