It's a mantra I learned 25 years ago when I began doing advance work for George H.W. Bush, which entailed working with the Secret Service to scout out the vice president's appearances and produce a minute-by-minute itinerary. At first, I was assigned to the less-glamorous destinations (Butler, Pa). Later, some of the assignments were plums (Brussels).

One of the first events I was given was right here in Warminster, at the Johnsville Naval Air Development Station. Vice President Bush was to deliver a speech in an aircraft hangar, and I was in charge of the site logistics.

As I surveyed the room 20 minutes before the vice president and the press traveling with him arrived in Warminster, I saw that we'd overestimated the number of chairs needed. In other words, there were plenty of empties.

So I ordered the unused ones immediately removed.

That's because of another rule for advance men: The image shown to people at home via TV trumps the one in the room. And a room that looked anything less than packed wasn't the picture we wanted.

I was thinking about this while watching the fallout from the conduct of some Obama campaign volunteers working at a rally in Detroit. By now you've heard the story of Hebba Aref and Shimaa Abdelfadeel.

They were part of two groups invited to upgrade their seats to perhaps the most prime real estate at Joe Louis Arena: Behind the podium, close to the candidate, in full view of the cameras broadcasting Obama's remarks.

But the women never got to those seats. They said that Obama volunteers had denied them those seats because of their Muslim head scarves. Aref said that her group was told that the scarves would be a problem in the "sensitive political climate."

In other words, misinformation is being spread that Obama is a Muslim who was sworn into office with his hand on a Koran. And, presumably, the volunteers thought they'd be fueling Internet rumors about the candidate's religion if they allowed the women to sit right behind him.

That misinformation has found an audience broad enough to warrant concern. Polling by the Pew Research Center indicates that one in 10 registered voters believes Obama is secretly a Muslim. And that 10 percent continues to flummox his campaign.

EVEN THE vehicle

the campaign rolled

out this month to fight what it considers untrue charges (fightthesmears.com) has stirred commotion. Some Muslims wonder why the campaign considers being called a Muslim a "smear."

Rep. Keith Ellison, an actual Muslim, says fellow Muslims haven't been "fully engaged" in Obama's message of inclusion, and says he was recently asked not to speak in a mosque on Obama's behalf.

Obviously the campaign volunteers erred when they denied the women their promised seats. They violated the first rule of advance: they did harm, and it was both predictable and avoidable.

But there is a bigger danger.

The Obama campaign will never be able to entirely thwart the knuckleheads who wish to do him injury.

Instead of over-reacting to those online assaults, the campaign must be careful not to turn off those who are enticed by the promise that this candidate is different - that he represents change from the status quo.

Denying Muslim women access to visible seating was politically expedient, in the short term. It was also at odds with the public persona the campaign has carefully crafted for Obama for more than a year.

On the heels of changing his position on public finance when it suited him, Barack Obama can ill afford yet another episode where his campaign looks like politics as usual. *

Listen to Michael Smerconish weekdays 5-9 a.m. on the Big Talker, 1210/AM. Read him Sundays in the Inquirer. Contact him via the Web at www.mastalk.com.