In advance of the May Day anniversary of Osama bin Laden’s assassination, the Obama reelection campaign is out with a new web ad, this one narrated by Bill Clinton who, echoing the words of another former president, praises Obama as “decider in chief.” The bin Laden operation was risky for Obama, Clinton says — if the intelligence was wrong or if the Navy Seals were captured or killed, “the downside would have been horrible” — but “that’s what you hire a president to do. You hire a president to make the calls when no one else can do it.”