It was not a lesson Lawrence Summers mastered with great ease. But after nearly a decade working beside sphinxlike Alan Greenspan, and having watched his own tenure as president of Harvard cut short by a phrase that slipped too nimbly from brain to mouth, Summers, director of the President’s National Economic Council, has become a restrained public man. Gone are the days when he would glibly compare flailing financial markets to jet crashes, as he did to TIME in 1999. He is mindful of how ill-considered asides by policymakers can cause financial-market angina. So you can probably imagine the ripple that ran through the Peterson Institute for International Economics in Washington in July when Summers looked up from his prepared speech, flashed a grin and loosed the sort of utterance that once upon a time marked imminent indiscretion. “There was,” he told the room, “a fight about whether I was allowed to say this now that I work in the White House…