The economic data are almost uniformly bleak and will not improve soon, and, while national security issues appear less pressing because of the financial crisis, they have hardly disappeared, given the tenuous situation in Afghanistan and Pakistan and the unresolved problems in Iraq, Iran, and North Korea. Moreover, the power of America’s presidency, and of the United States, has undergone dramatic shifts in recent years, making our era unlike earlier periods when the world was in flux and a new American president faced deep challenges.