But the question remains as to whether the now-likely outcome -- transforming a virulently aggressive enemy state in the heart of the Middle East into a strategic ally in the war on terror -- was worth it. I suspect the ultimate answer will be far more favorable than it is today.

When I asked the president about his one unambiguous achievement, keeping us safe for seven years -- about 6 1/2 years longer than anybody thought possible at the time of 9/11 -- he was quick to credit both the soldiers keeping the enemy at bay abroad and the posse of law enforcement and intelligence officials hardening our defenses at home.

But he alluded also to some of the measures he had undertaken, including "listening in on the enemy" and "asking hardened killers about their plans." The CIA has already told us that interrogation of high-value terrorists like Khalid Sheik Mohammed yielded more valuable intelligence than any other source. In talking about these measures, the president mentioned neither this testimony as to their efficacy nor the campaign of vilification against him that these measures occasioned. More equanimity still.

What the president did note with some pride, however, is that beyond preventing a second attack, he is bequeathing to his successor the kinds of powers and institutions the next president will need to prevent further attack and successfully prosecute the long war. And indeed, he does leave behind a Department of Homeland Security, reorganized intelligence services with newly developed capacities to share information, and a revised FISA regime that grants broader and modernized wiretapping authority.

In this respect, Bush is much like Truman, who developed the sinews of war for a new era (the Department of Defense, the CIA, the NSA), expanded the powers of the presidency, established a new doctrine for active intervention abroad, and ultimately engaged in a war (Korea) -- also absent an attack on the U.S. -- that proved highly unpopular.

So unpopular that Truman left office disparaged and highly out of favor. History has revised that verdict. I have little doubt that Bush will be the subject of a similar reconsideration.