Behind the scenes, Sean Noble, with the assent of the Kochs, had been furtively trying for months to persuade Paul Ryan to run for the White House. The billionaire backers were eager for him to apply his “sharp knives” to the federal budget. But Ryan had demurred. Neither he nor his wife relished a presidential marathon. “Wouldn’t it be easier just to be picked as vice president?” he asked an emissary from the Kochs, in a meeting in the congressman’s Washington office. “Because then it’s only, like, two months.”