A kid among kids, this presidential candidate: smirking, laughing, wig-waggling his shrubby eyebrows. Crack a joke, slap a palm, look those little kids from the Boys and Girls Club right in the eye and go goofy.

Meanwhile, his political sixth sense twitches like a mouse on a hot plate.

He knows just which little black or brown kid to hug. How to catch the camera angles. (The advance guys spent a day positioning the klieg lights just so.) Where the reporters are standing and when to shoot them the knowing wink that makes 'em feel like insiders.

The glint in his baby blues can be so charming.

George W. Bush may or may not know a Kosovian from a Timorian, but know this: The governor of Texas is a most natural pol. He's the adolescent screen star going adult, the Michael J. Fox of presidential politics.

To watch him work a hall, a crowd, a knot of reporters, is to watch a youngish man of 53 backstroking in a dynastic pool. His rap is mainline conservative, but with an insistence--unusual in a Republican stemwinder--that society must help those who are not swimming in the gilded waters.

And unlike his old man, George W. hails from the Bill Clinton school of tactile touching: He's got the jock's jaunty strut, the hand on grandma's elbow, the loose-limbed arm draped over a factory worker's shoulder. He tells the same self-deprecating joke four times a day, and it rarely sounds less than freshly minted.

"My wife said, 'You're fixin' to go to Iowa, you'll probably want to impress," Bush says. " 'Don't try to be debonair, witty or charming. Just be yourself.

" '. . . And whatever you do, don't show off and start naming all the world leaders.' "

That one gets the big ha-ha! Oh yeah, laughter runs electric. But here's the problem for Bush. The joke hums because it goes bone deep.

Three weeks ago, Bush is sprinting so far out in front of the presidential parade that aides are measuring East Wing drapes. He's got a campaign warehouse piled high with cash and a list of endorsements that reads like the agate in the Federal Register.

Then a reporter gets him in a television studio and Bush can't name some little-known leaders of some pretty big global trouble spots. He takes another hit in the gravitas this week when he reads to an Associated Press reporter a quote from his foreign policy speech: ". . . if the Russian government attacks innocent women and children in Chechnya."

Aren't the Russians doing that now? the reporter asks.

At this, Bush reportedly moves the telephone from his mouth and shouts to an adviser: "They are attacking women and children, aren't they?"

Assured that this is so, Bush tells the reporter that his adviser is "shaking her head in agreement."

By now, Washington's closed loop of pundits and pols is vibrating: Just how shallow is the frontrunner? Prince Hal is only charming if you know he'll ditch Falstaff and morph into King Henry V.

Fair or not, it's a longstanding critique. When Bush announced his candidacy for governor six years ago, he himself noted that critics charged that "I was a lightweight trading on a famous name."

It's trickier to maneuver than one might guess. American history offers many examples of presidential candidates--George Romney, anyone?--whom voters discarded after finding them to be not quite serious enough.

So how does Bush avoid Dan Quayle's potato[e]-ized fate?

Write a book! The author's path, as any tenure-yearning junior professor knows, is a quick way to acquire tweedy substantiveness. So Bush and his campaign churned out his autobiography, "A Charge to Keep," and took it on the road.

Unveiled on his campaign swing here, the book is a generically readable and modestly unrevealing effort, "The Hardy Boys and the Quest for the Presidency."

The template is straightforward: Bush styles himself a West Texas boy; he's got twin girls and a lovely wife and great parents; in college, there is Vietnam, but he and his friends don't talk about it much. Then he worries a little about the draft. He tries hard in business but fails a lot. Then he becomes rich. He loses his first political race, wins his second and makes some tough decisions on the death penalty.

His dog is named Spot.

If "A Charge to Keep" falls short of tomes written or ghost-written by such literati politicians as John McCain, Al Gore and Bill Bradley, it would cause no shame if piled like cord wood alongside the books of most career politicians.

In fact, it is Bush's charm that he makes no broader claim for the book or himself. He freely gives the writing credit to his spokeswoman Karen Hughes. And he apologizes if he is boring a reader.

In this way, the book seems of a piece with the man. He's no fan of the "public strip search" on matters of drugs, sex and rock-and-roll. But he'll chatter on and on about the comfortable truisms of family life.

His strength is living on the stump. Campaigning through eastern Iowa, careening across an autumnal country of barren browns and fields stripped bare of green, he's full of winks and confidential nods.

On Wednesday, he rolls into Clinton, a fading industrial city on the western banks of the Mississippi River. He's just given a speech at the Best Western and a diminutive blue-haired lady wanders up and presses wrinkled paper into his hand to read.

"You think I can read that without my glasses?" He bounces into a low crouch, so he can peer directly into her slightly startled face. "You're an optimist!"

He cracks up.

It's something of an unpredictable ride, swinging from pretty funny to a little menacing. A couple of minutes later, he's still shaking hands, cracking jokes with the locals, and all of a sudden he espies a reporter taking notes. He puts on the Roman candle stare that made him such a terror when he was doing the est scream stuff to the press in his father's presidential campaigns.

"You takin' notes?" It's not a hostile inquiry, but it's not friendly either. "This isn't a press conference, you know."

Just taking notes on your style, a reporter replies.

Some of the edginess drains from his smile. He assays a runway model's aspect, sticking out his toes. "Nice pair of loafers, huh?"

You're never quite sure if you're in on the joke or the butt of it.

Then there's the matter of Bush's stump speech, which is heavily inflected with a pol't'cian's faux and gloriously loopy folksiness.

"If there aren't 'nuf jobs, it's hard to keep livin'," Bush tells the folks at the Best Western. "You folks knowin' and livin' that."

This is the G as an endangered letter, Yale-and-Harvard-by-way-of-Andover George W. talkin' about learnin', readin', doin', livin' and fixin'. (It should be noted that Harvard-by-way-of-St. Albans Albert Gore also seems at risk of losing the letter G these days).

Beneath the easy retail rap, however, resides an edginess, a hesitancy about how his personality is being shaped and defined in the cartwheel of the campaign trail. At the Boys and Girls Club in Davenport he finishes with a few jokes, gets a good wash of applause. Then he sidles over to a stairwell, moves in real close to five reporters and starts talking. Yes, yes, the American people have a right to ask about foreign policy . . . these are important issues . . . there'll be news in his foreign policy speech in California . . . maybe not news news, but news . . . just wait . . . he knows what he thinks in his heart . . .

What about this idea that you don't quite get it, a reporter asks.

You wait but this time there's no Roman candle. He's doing the tactile thing, putting a hand on the reporter's shoulder. "I think the clock is running out on that [criticism]," he says.

He walks away, goes up the stairs two at a time with that slight bop. It's the bearable lightness of George W. Bush.