Conventional wisdom holds that U.S. Attorney Patrick Fitzgerald ordered the FBI to arrest Rod Blagojevich before sunrise Tuesday in order to stop a crime from being committed. That would have been the sale of the Senate seat vacated by President-elect Barack Obama. But the opposite is true: Members of Fitzgerald’s team are livid the scheme didn’t advance, at least for a little longer, according to some people close to Fitzgerald’s office. Why? Because had the plot unfolded, they might have had an opportunity most feds can only dream of: A chance to catch the sale of a Senate seat on...