As the year 2001 unfolded, the United States stood at the apex of global power, possessing unrivalled military capabilities, a vibrant economy, and--most of all--great self-confidence about its security. The terrorist attacks of 9/11 shattered America's prevailing illusions of invulnerability, prompting the world's sole superpower to embark on a revolutionary national strategy that led to a preventive war against Iraq. Will the United States be safer...