On an ordinary day, Henry Aaron, senior fellow in economic studies at the Brookings Institution in Washington, comes across as the quintessential policy wonk: knowledgeable, thoughtful, measured, perhaps even a tad boring. With his rumpled suits, snowy hair, and rosy jowls, the genial septuagenarian brings to mind one's favorite uncle--assuming that uncle had spent the past 40 years exploring tax policy, health care financing, and the intricacies of sprawling entitlement programs.

In the tumultuous history of postwar American conservatism, defeats have often contained the seeds of future victory. In 1954, the movement's first national tribune, Senator Joseph McCarthy, was checkmated by the Eisenhower administration and then "condemned" by his Senate colleagues. But the episode, and the passions it aroused, led to the founding of National Review, the movement's first serious political journal. Ten years later, the right's next leader, Barry Goldwater, suffered one of the most lopsided losses in election history.

On his first day in office, President Barack Obama will head to the situation room for a video conference with his most important commander, General David Petraeus. If the conversation is chilly, it is not just the awkwardness of virtual chatting. Obama and Petraeus have a history. While Obama has called for withdrawing U.S. forces from Iraq, Petraeus oversaw the deployment of more than 30,000 additional troops. To win support from the left, Obama postured as a skeptic of the general's Iraq strategy during congressional hearings.