The Obama policies also reflect the fact that the Bush policies were woven into the fabric of the national security architecture in ways that were hard if not impossible to unravel. The new administration would not face the difficulties of closing GTMO if GTMO had not been used as a detention facility in the first place. It would have an easier time prosecuting some terrorist suspects in civilian courts had information about their crimes not been extracted through coercion (assuming, that is, that it would have nabbed the suspects in the absence of the information gained through coercion). And so on. It is impossible to know how an Obama (or any other) administration would have dealt with the manifold terrorist challenges beginning on 9/11, or how the world might look different today if the Bush administration had made different decisions. But no doubt some of the Obama agreement with Bush policies reflects the fact that Obama inherited challenges that were created by decisions with which he would not have agreed.

A third reason for the closeness of the Bush and Obama policies is that many of the Bush policies reflect longstanding executive branch positions. Every wartime president has asserted the right to detain enemy forces without charge or trial during war. Many of them used military commissions for war criminals. Presidents dating back at least to Carter have maintained that habeas corpus review does not extend to aliens detained outside the United States. The state secrets doctrine is over a century old and has been employed vigorously by presidents since the 1970s. Rendition and targeted killings began under Clinton if not earlier. It is no surprise that President Obama seeks to maintain these presidential powers. It would be a surprise if he did not do so.

A final explanation for the congruence between Obama and Bush policies is that governing is much harder than campaigning. The presidency invariably gives its occupants a sober outlook on problems of national security. The "responsibilities placed on the United States are greater than I imagined them to be, and there are greater limitations upon our ability to bring about a favorable result than I had imagined them to be," said President John F. Kennedy, nearly two years into his presidency. "There is such a difference between those who advise or speak or legislate, and between the man who must select from the various alternatives proposed and say that this shall be the policy of the United States. It is much easier to make the speeches than it is to finally make the judgments."

President Obama has gone from a legislator and presidential candidate to the commander in chief wholly responsible for the nation's safety. He now reads the same threat reports as President Bush and confronts the same challenge of stopping Islamist terrorists who hide among civilians and who want to use ever-smaller and more deadly weapons to disrupt our way of life. He also faces the same paucity of truly useful information about the enemy and the same hard tradeoffs between liberty and security. And he knows that the American people will blame him and no one else if the terrorists strike. "The whole government is so identified in the minds of the people with [the president's] personality," said William Howard Taft, "that they make him responsible for all the sins of omission and of commission of society at large." The intense personal responsibility of the president for national security, combined with the continuing reality of a frightening and difficult-to-detect threat, has unsurprisingly led President Obama, like President Bush, to want to use the full arsenal of presidential tools