Not since Robert McNamara has a secretary of defense been so hated by the military and derided by the public, yet played such a critical role in national security policy—with such disastrous results.

Donald Rumsfeld was a natural for secretary of defense, a position he'd already occupied once before. He was smart. He worked hard. He was skeptical of the status quo in military affairs and dedicated to high-tech innovations. He seemed the right man at the right time-but history was to prove otherwise.

Now Dale Herspring, a political conservative and lifelong Republican, offers a nonpartisan assessment of Rumsfeld's impact on the U.S. military establishment from 2001 to 2006, focusing especially on the Iraq War-from the decision to invade through the development and execution of operational strategy and the enormous failures associated with the postwar reconstruction of Iraq.

Extending the critique of civil-military relations he began in The Pentagon and the Presidency, Herspring highlights the relationship between the secretary and senior military leadership, showing how Rumsfeld and a handful of advisers—notably Paul Wolfowitz and Douglas Feith—manipulated intelligence and often ignored the military in order to implement their policies. And he demonstrates that the secretary's domineering leadership style and trademark arrogance undermined his vision for both military transformation and Iraq.

Herspring shows that, contrary to his public deference to the generals, Rumsfeld dictated strategy and operations—sometimes even tactics—to prove his transformation theories. He signed off on abolishing the Iraqi army, famously refused to see the need for a counterinsurgency plan, and seemed more than willing to tolerate the torture of prisoners. Meanwhile, the military became demoralized and junior officers left in droves.

Rumsfeld's Wars revisits and reignites the concept of "arrogance of power," once associated with our dogged failure to understand the true nature of a tragic war in Southeast Asia. It provides further evidence that success in military affairs is hard to achieve without mutual respect between civilian authorities and military leaders—and offers a definitive case study in how not to run the office of secretary of defense.