To say it's important to continue the drawdown, that isn't the way I think about it. It's important to achieve victory in Iraq; it's important to win, to succeed in the objective that we've established. The question about what force level that takes is a judgment that's made based upon the recommendations of the commander in the field. Obviously, we look at the advice, for example, from Ryan Crocker, our ambassador that's there, as well, too. All of this goes up through the chain of command in the Pentagon. The Joint Chiefs have an opportunity for input and advice. The secretary comes in. All of this goes to the president, the set of recommendations.

That's Vice President Dick Cheney, in an interview with ABC News. I found one of his formulations -- "a judgment that's made based upon the recommendations of the commander in the field" -- particularly interesting. It's by now well known that Gen. David Petraeus, the aforementioned commander in the field, is a favorite of the administration, and a supporter of current administration thinking about force levels in Iraq. On the other hand, commanders above Petraeus -- including, reportedly, members of the Joint Chiefs, whom Cheney mentions as having only "an opportunity for input and advice" -- disagree with Petraeus.

During the interview, Cheney also said:

I think if you look, for example, at what we've been able to accomplish in terms of the people captured and killed in the al-Qaida organization, and the fact that we put them on the run, the fact that we have successfully defended the country now for going on seven years against any further attacks -- there have been no additional attacks like 9/11 on the U.S. That's not an accident, that's because we've been very successful at going after bad guys, searching them out wherever we find them; because of the measures we've put in place at home -- the Terrorist Surveillance Program, the Patriot Act and so forth.

In fact, as author Ron Suskind and I discussed in a 2006 interview, the thinking inside the U.S. intelligence community is that the U.S. is "indefensible," that the lack of 9/11-level attacks on the U.S. since 2001 isn't a function of increased security but of a conscious decision by al-Qaida. During the interview, Suskind said:

The thinking is that al-Qaida has the ability to attack us at any time or place of their choosing, that we should not view the passage of time as a kind of proxy for victory and view it in any kind of self-satisfied way, that we're doing something that's stopping them from this next destructive moment. What we know about al-Qaida is that they think very long-term. We think in news cycles; they think in decades.

They have spent a good deal of energy thinking about what is appropriate to follow 9/11. It could take years for them to come up with something that is a sufficiently destructive next act in this drama that they are driving. If the next attack is bigger than 9/11, what it does is create an upward arc of terror and anticipation between that second act and whatever follows, however many years later. I think the other thing that's important here, that the book shows, is really, more than anything else, discretion. They're making decisions. They may not have actually been trying to attack the United States in these ensuing years. Even though folks in government have sort of been taking some credit for the fact that there hasn't been an attack, I think they know better.