By Tuesday night about 90 million Americans will have cast ballots in an election that’s almost certain to create greater partisan divisions, increase gridlock and render governance of our complex nation even more difficult. Ninety million sounds like a lot, but that means that less than 40 percent of the electorate will bother to vote... The main impact of the midterm election in the modern era has been to weaken the president, the only government official (other than the powerless vice president) elected by the entire nation. Since the end of World War II, the president’s party has on average...