Sometimes a blue suit is not just a blue suit.

President Clinton recently advised Vice President Gore to stop wearing so many blue suits. Loosen up a little, he said. It was hardly the first time fashion tips have made the politics page--generations of schoolchildren have learned the story of the little girl who told Abraham Lincoln to grow a beard.

But Clinton's advice wasn't sartorial. It was strategic. Philosopher of clothing Anne Hollander suspects the president had in mind the "capital B, capital S" Blue Suit-ness of blue suits--an essence that conveys dullness, convention, safety and, ultimately, boredom.

In other words, the Blue Suit-ness of the suit underlines the Al Gore-ness of Al Gore.

Such talk definitely fits into the category "Bad Breaks for Gore." For a candidate, the only thing worse than wearing the wrong clothes is having people discuss the wrong clothes you are wearing.

It is possible to dress dully or even badly and do fine in politics; if you don't believe that, spend an afternoon observing the House of Representatives. It can be trouble, though, if people start to notice. Former Tennessee governor Lamar Alexander ran for president in 1996 wearing a red-and-black plaid shirt. Probably he wished to convey the message that he is vigorous and populist and outdoorsy and manly. Instead, as he has noted, his shirt got more attention than he did. Meanwhile, Republican primary voters apparently decided they did not need a lumberjack in the White House.

A single bad clothing day wreaked havoc on Michael S. Dukakis's campaign. The 1988 Democratic presidential nominee--ignoring that age-old political nostrum, never put on the hat--strapped on a helmet and boarded a tank. He looked like he was on his way to visit Snoopy's flying doghouse.

Nothing made Richard M. Nixon, America's lonely president, seem more alien and isolated than the image of him beside the sea, walking pensively on the beach in a pair of wingtips.

Now, the predictable response to all this is: Tsk, tsk. Image over substance. Why can't we talk about the issues?

As Clinton's advice suggests, though, even policy gearheads realize that how a leader--especially a candidate for president--looks speaks directly and deeply to the voting public. It was no accident that, despite the heat of war, Dwight D. Eisenhower, supreme allied commander, found time to design a trim little tunic that looked so well on him it became the enduring fashion staple known as the Eisenhower jacket.

Decades later, Gen. Colin L. Powell prepared for his retirement with a visit to legendary tailor Martin Greenfield. Powell said he was going to need "a new uniform." "He looks so good because he loves to dress," Greenfield said after crafting a closetful of gorgeous suits for Citizen Powell.

Clothes can come to sum up a leader as well as any quotation or gesture. This can be negative: how President Jimmy Carter must have regretted his Mr. Rogers cardigans when the odor of weakness began to fall on his presidency.

It can be positive: Think of Theodore Roosevelt, bully on American empire, practically bursting out of his safari gear. Or another Roosevelt, Franklin, whose legislation, rhetoric and cigarette holder all pointed just one way: up. John F. Kennedy, whose glamour haunts Democrats to this day, could do it all, from bare chest to white tie. But the essential Kennedy--the beauty, the verve, the insouciance and recklessness--could be distilled to a pair of sunglasses and a thick shock of hair.

All the successes have one thing in common, says Hollander: "You have to believe in what you're wearing when you have it on. You must have the same conviction in your clothing as an animal has in its pelt."

Which brings us, inevitably, to Ronald Reagan. All discussions of modern political image-making come back to The Master.

Did Reagan wear Blue Suits? Sure, but no one complained. Reagan could wear anything--brown suits with huge plaids, like Prof. Harold Hill in "The Music Man," sweaters, cowboy hats, shirts with mother-of-pearl buttons. Even lumberjack shirts. "Years ago, there was some sort of boat party in Sacramento. He had on a white blazer, really awful," Reagan adviser Michael K. Deaver remembers.

"I said to my wife, 'Did you see that coat he has on?' And Carolyn said, 'Mike, it doesn't matter. People are never looking at his clothes.' "

The secret, says Deaver, was "how comfortable he was in his own skin. You see, nobody ever talked about what Harry Truman wore. Why?" Deaver quotes Truman biographer David McCullough: "There was nobody he would rather be."

Can the same be said of Al Gore?

If the key to political dressing is comfort and conviction, Gore is in a bad spot right now. He is a product and master of Washington culture, and his natural plumage is a Blue Suit. Blue Suits are to the capital what black dresses are to Manhattan--the eternal uniform. Even when the Blue Suit happens to be gray, as Gore's was in Texas last week.

The day captured the problem entirely. Appearing beside his president and fashion counselor, Gore's gray pinstripe exuded Blue Suit-ness: boxy cut, bland fabric, off-the-rack fit. Later, he changed into a polo shirt, but instead of seeming relaxed he seemed scripted. He suffered for needing the president's advice and he suffered for heeding it.

Hollander's solution is simple: "Not fewer suits. Better suits." Consider what Martin Greenfield has managed for Clinton, who has gone from sweatshirted chub to sleek fashion plate since putting himself in skilled hands.

A final Reagan story: "Early on, he taught me a great secret of communications," says Deaver. "He was governor of California and NBC wanted to follow him around for a day. This was a big deal. So I worked a storyboard for the day. The first thing we'll do, I told him, is go out in the park. You'll sling your coat over your shoulder and walk along pensively.

"He said, 'Mike, I can't do it. I don't go around with my jacket off. So if I do it for the cameras I'll feel uncomfortable. And if I'm uncomfortable, the people watching me are going to be uncomfortable.' I never forgot that lesson."

CAPTION: President Clinton and Vice President Gore--before taking Clinton's fashion advice--spoke in Edinburgh, Tex., last Tuesday.

CAPTION: After the speech, Gore changed his style, trading his usual boxy suit for a polo shirt.