Incidentally, Donald Trump was the only candidate who challenged Rubio’s premise, dismissing Obama as a rank incompetent. But whether or not you like what Obama has done, and none of the Republican candidates do, Rubio is correct that he has done an awful lot, transforming U.S. policy not only on health care, economics, financial regulation, and Iran, but also on energy, education, taxation, gay rights, Iraq, Cuba, and much more. Rubio’s opponents have dismissed him as a Republican version of Obama — charismatic and inspiring but ultimately too young and inexperienced for the job. Rubio was essentially implying, but not quite daring to say out loud, that Republicans need their own version of Obama to reverse what he’s done.

Of course, one thing Obama has done is win two national elections. Rubio’s candidacy has benefited from a widespread belief that he would be the most electable Republican, a Cuban-American from humble roots, a natural politician with a stirring personal story who would look like tomorrow against Hillary Clinton’s yesterday. But that aura of electability took a big hit last night when he started to sound like a broken record and look like an empty suit. He certainly didn’t seem like someone who knew what he was doing.