Extremist-in-chief George W. Bush yesterday continued along his merry way, going over the heads of the wise men and defying Washington moderation and the glories of bipartisan centrism to remind the American public that he is also the protector.

"The only way to secure a lasting peace for our children and grandchildren is to defeat the extremist ideologies," the president said.

Mark his words: the only way.

Those yearning for a tidier world can produce studies and recommendations galore, but the president firmly believes he is the one who has to deal with the real world, and that he and not the ivory tower uniquely understands how dangerous it is.

Thus we are witnessing the emergence of a new divide in American politics. It is no longer Democrats vs. Republicans or withdrawers vs. stay-the-coursers. The majority, bucked up by strong majority in American public opinion, is clearly in favor of change. In English, that means it's over in Iraq.

The new battleground will be between the believers and the non-believers. Bush and Cheney command the believers, who remain the custodians of the Sept. 11 aesthetic that America and the world are threatened, leaving no room for niceties and togetherness.

But it is not just Bush and Cheney, and the Washington-New York-Hollywood axis should take notice. The protectors are mobilizing. They see American "will" dwindling and think they need to do something about it.

In our naïve ways, we might believe that that means they have to change policy. But in the ways of national security, the protectors believe just the opposite….

Nowhere is this more resonant than in what it says about the Pentagon. For it was the Pentagon that ran the administration's Iraq policy, and the senior civilian officials - Donald Rumsfeld, Paul Wolfowitz and Douglas Feith - who did things their own way and marginalized any service chiefs who disagreed with them.

But the Pentagon ran the policy because the president allowed and encouraged them to do so. This was a huge disfigurement of the traditional inter-agency way of doing things, in which the president, as commander-in-chief, was supposed to make the decisions after taking advice from the inter-agency policy-making apparatus coordinated by the national security adviser.

When the government tells you that you can't smoke marijuana or that you must wear a helmet when you ride your motorcycle even if you happen to like the feeling of the wind in your hair, it is being paternalistic. It is largely treating you the way a parent treats a child, restricting your liberty for what it deems to be your own good. Paternalistic laws aren't very popular in this country. We hew to the principle that, children and the mentally ill apart, an individual is a better judge of what's good for him than the state is and that people should be free to do what they wish as long as their actions don't harm others. Contrary to what many people believe, you can even commit suicide legally (although if you don't live in Oregon, you should think twice about seeking assistance).

But what if it could be shown that even highly competent, well-informed people fail to make choices in their best interest? And what if the government could somehow step in and nudge them in the right direction without interfering with their liberty, or at least not very much? Welcome to the new world of "soft paternalism." The old "hard" paternalism says, We know what's best for you, and we'll force you to do it. By contrast, soft paternalism says, You know what's best for you, and we'll help you to do it.

To begin with, they don't like soft paternalism when it involves the state's coercive power; they are much happier with private self-binding schemes, like alcoholism clinics, Christmas savings clubs and Weight Watchers. They also worry that soft paternalism can be a slippery slope to the harder variety, as when campaigns to discourage smoking give way to "sin taxes" and outright bans. But some libertarians have deeper misgivings. What bothers them is the way soft paternalism relies for its justification on the notion that each of us contains multiple selves - and that one of those selves is worth more than the others.

You might naïvely imagine that you are one person, the same entity from day to day. To the 18th-century philosopher David Hume, however, the idea of a permanent "I" was a fiction. Our mind, Hume wrote, "is nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement." According to this way of thinking, the self that inhabits your body today is only similar to, not identical with, the self that is going to inhabit your body tomorrow. And the self that will inhabit your body decades hence? A virtual stranger.

… Further evidence for the fragmented self comes from neuroscience. Brain scans show that the emotional part of the brain, the limbic system, is especially active when the prospect of immediate gratification presents itself. But choice among longer-term options triggers more activity in the "reasoning" part of the brain, located (suitably enough) higher up in the cortex. Now suppose you're tempted by a diet-violating Twinkie. Which part of your brain - the shortsighted emotional part or the farsighted reasoning part - gets to be the decider? There may be no built-in hierarchy here, just two autonomous brain modules in competition. That is why you might find yourself eating the Twinkie even while knowing it's bad for you. (A similar disconnect between two parts of your brain occurs when a visual illusion doesn't go away even after you learn it's an illusion.)

The short-run self cares only about the present. It is perfectly happy to indulge today and offload the costs onto future selves.