It was a tranquil summer Sunday in the normally frantic capital of the free world. A reader named Brian was riding his bike south on 16th Street, just above Scott Circle.

Suddenly, here came a virtual platoon of emergency vehicles. "I counted 14," Brian told me the next day. "Police cars, motorcycles, big black sport-utility vehicles. And a limousine."

Inside it, I later learned, was the president of the United States. He had attended church and was returning to the White House.

"I'm not saying he should have walked, Bob," Brian told me. "But I was mucho annoyed by the way this convoy handled itself.

"They were going at least 35 miles an hour. They had their emergency lights and sirens going. And there was no emergency! It was a quiet Sunday. Why couldn't they have driven at normal speeds, without the fanfare?"

The reason, of course, is security. Since 1963, two presidents have been shot and another nearly joined them. Presidents are always assumed to be targets, I told Brian.

He didn't buy my reasoning.

"This was a politician inside that limousine, Bob. And I don't mean just because it was Clinton. Every president is a politician. Why does he have to travel as if he's in such a huge hurry to protect the national interest?

"What if he were going to a political fund-raiser? He'd get the same sirens, even though he wouldn't be doing official business."

Brian asked me to back a campaign to separate official motorcades from unofficial ones -- or to get security officials to turn off their sirens on quiet Sunday afternoons. I had to tell him no twice.

Assume that you were an assassin. Wouldn't you want to strike when resistance was lowest? That's why protection is never lower on Sundays than it is the rest of the week -- and that's why there's no such thing as an unofficial motorcade.

Whenever the president is out and about, he gets the best and most subtle effort that the Secret Service can offer.

If Brian had happened past the church where the president attended services, he would have noticed agents. But they wouldn't have gotten in the way of worshipers. They would have protected the president, but they wouldn't have prevented anyone else from saying prayers or singing hymns.

As I told Brian, one benefit of a speedy presidential motorcade is that sirens are gone faster than they would be if security personnel observed the speed limit. And it doesn't matter that the president had only 15 blocks to travel between church and the White House. President Ronald Reagan was only 20 blocks from the White House when he was shot.

Perhaps this is mostly a generation gap story. Brian said he wasn't alive during the Kennedy and Ford administrations, and barely remembers the Reagan shooting, outside the Washington Hilton Hotel.

Others remember it entirely too well.

Still miss the Washington Senators? Me, too. But Nats News may dull the pain.

Nats News is the publication of the Washington Baseball Historical Society. Henry Fankhauser, a WBHS member, sent along a recent item that made me chuckle. It stars Jimmy Piersall, once a Washington outfielder and the father of nine children.

Almost no one uses fold-them-yourself diapers any more. But Piersall did, as the following proves. It's his advice on how to diaper a baby:

"Spread the diaper in the position of the diamond with you at bat. Then fold second base down to home and set the baby on the pitcher's mound. Put first base and third together, bring up home plate and pin the three together.

"Of course, in case of rain, you gotta call the game and start all over again."

To join WBHS, write to P.O. Box 223661, Chantilly, Va. 20153, or call Tom Holster at 703-925-0873.

SEND A KID TO CAMP

If this is Wednesday, it must be time to chow down at McCormick & Schmick's Seafood Restaurants for the greater glory of our annual fund-raising campaign.

If you order seafood and corn chowder today at McCormick & Schmick's (Reston Town Center or 17th and K streets NW), every cent you spend will help us send underprivileged kids to summer camp. Same goes if you order blackened steak Caesar salad at the M&S Grill (13th and F streets NW).

Calories and camp -- it has a neat ring, doesn't it? So would a hearty jingle of our camp cash register. Many thanks in advance.

Our goal by July 30: $550,000.

In hand as of July 15: $255,713.02.

CONTRIBUTE TO THE CAMPAIGN:

Make a check or money order payable to Send a Kid to Camp and mail it to Bob Levey, The Washington Post, Washington, D.C. 20071.

VISA OR MASTERCARD:

Call Post-Haste at 202-334-9000 on a touch-tone phone. Then punch in K-I-D-S, or 5437, and follow instructions.