Soon after the November elections leading Democrats agreed that the party was ailing and in dire need of a new direction, a new focus, new ideas to lead it forward. "It's critical we realize why the electorate voted the way it did," Representative Bob Menendez, of New Jersey, the chairman of the House Democratic Caucus, said of the party's devastating loss in the presidential election and its setbacks in both houses of Congress. In February, House Democratic lawmakers held a retreat in Virginia to hash out what to do next. Something miraculous happened. They recovered—or at least they're behaving that...