Have you seen the advertising campaign for "the new Chrysler"? Slogan: "If you can dream it, we can build it." Sounds like an ad for a California custom shop. But more important, is the slogan memorable? In this day and age, it doesn't matter how well-crafted the words are; if the slogan isn't memorable, it's just a waste of space.

"It's all inside" is the slogan of a department store. Maybe everything you might want to buy is inside that department store, but who is going to remember that forgettable line? It's the slogan of JCPenney, a brand without a clear identity.

If you want an effective, long-term rallying cry for your brand, you need a slogan that sticks in the mind. A sticky slogan can live forever.

"Liberte. Egalite. Fraternite" was the slogan of the French Revolution more than 200 years ago. Yet the slogan still stirs the hearts of freedom-loving people everywhere. On the other hand, the slogan of the American Revolution, "Don't tread on me," is mostly forgotten today. Even a minor war, such as the Spanish-American war of 1898, can generate a memorable slogan: "Remember the Maine." And the first World War will always be remembered by the unforgettable slogan "The war to end all wars."

What makes a slogan memorable or sticky? Here are four mental "glues" that can help paste your message in the consumer's mind.

Rhyme and alliteration
Gerry Spence is known as the "best trial lawyer in America." In 41 years, he never lost a criminal jury trail. According to one source: "He no sooner makes the decision to take on a client than he drafts his closing statement, coming up with a catchphrase he repeats throughout the trial."

"Let us select a phrase, a theme, a slogan that represents the principal point of our argument," Mr. Spence wrote. "The theme can summarize a story that stands for the ultimate point we want to make."

In one case, he told the jury a story about a man who brought a lion onto his property that somehow escaped and mauled his neighbor. Mr. Spence related that story to a case against Kerr-McGee Corp., which, he claimed, had stored an inherently dangerous substance on its premises. "If the lion gets away, Kerr-McGee must pay." And it did.

That was the same strategy used by Johnnie Cochran in the O.J. Simpson case: "If it doesn't fit, you must acquit."

Alliteration is a good strategy for choosing brand names. Some examples: Coca-Cola, Bed Bath & Beyond, Grey Goose, Magic Markers, Chris Craft, California Closets, Dirt Devil.

Combining an alliterative brand name with a slogan that rhymes or trips off the tongue can be particularly powerful. Think: "Roto Rooter. That's the name. And away go troubles down the drain." Or M&Ms: "Melts in your mouth -- not in your hand." And then there's Timex: "Takes a lickin' and keeps on tickin'." Lexus scores with "The passionate pursuit of perfection." (Mercedes-Benz should have pre-empted that idea years ago.)

Then there's Ace Hardware's longtime slogan "Ace is the place with the helpful hardware man." Because of the gender problem, the slogan was shortened to "The helpful place." You know what? "The helpful place" might be shorter, and it might communicate the same benefit, but it loses the poetry and is not as memorable as the original.

"Don't squeeze the Charmin" says the same thing as "Please don't squeeze the Charmin," but it isn't as memorable.

Double entendre
Another effective mental glue is the double entendre. Some examples: "Nothing runs like a Deere"; "Nothing can stop a Trane"; "When it rains, it pours"; "A diamond is forever."

"We must hang together," Benjamin Franklin once wrote, "or assuredly we will all hang separately." It's a political statement that still sticks in many people's minds.

Perhaps the most effective political slogan ever written was conceived by Saatchi & Saatchi on behalf of the Conservative Party before the 1979 U.K. general election. "Labour isn't working," said the headline on an ad that pictured a long, winding line of people in front of an unemployment office. (Margaret Thatcher won that election.)

Even brand names can use double entendres. Take Staples, the office superstore, for example. When a word like "Staples" has two different meanings, it activates two separate places in your mind. First you think of one meaning (a U-shaped piece of metal) and then another (everything a business needs). The vibration between the two meanings helps lock the word into your memory.

Cuba Libre is the name of a mixed drink of rum, Coke and lime juice. It also means "Free Cuba." For years I have felt that Bacardi, a liquor company that was thrown out of Cuba by Fidel Castro, should promote rum and Coke under the banner of "Cuba Libre": Drink Bacardi rum and Coke and pray for the day Cuba will be free again.

Repetition
Of the four mental glues, repetition is the slogan strategy that is most underused. I suspect it's because of the pressure to simplify, simplify, simplify.

Federal Express didn't get off the ground with the slogan "When it has to be there overnight." Rather, the ad agency Carl Ally added two words that made all the difference: "When it absolutely, positively has to be there overnight." Even today, you'll find the words "absolutely, positively" used in news stories about FedEx.

Newcastle Brown Ale is "The one and only," not just "The one."

Reversals
In literature, memorable ideas often are expressed in polar opposites, or reversals. "To be or not to be: that is the question" is perhaps Shakespeare's most famous line. "And so, my fellow Americans, ask not what your country can do for you ..." is the first half of Jack Kennedy's most famous line.

Reversals are memorable for the same reason double entendres are memorable: They vibrate between two meanings, forever embedding a concept in consumers' minds.

Charles Dickens: "It was the best of times, it was the worst of times." T.S. Eliot: "This is the way the world ends. Not with a bang but a whimper." Robert Frost: "Some say the world will end in fire, some say in ice."

The late Charles Revson borrowed from Frost and introduced Revlon Fire & Ice, which became the cosmetics company's most successful product line.

Also memorable are a Holiday Inn slogan that ran for quite a while, "The best surprise is no surprise," and Reese's Peanut Butter Cups' "Two great tastes that taste great together."

Then there's Fresh Direct, a company that took Webvan's concept of grocery delivery and made it work. Fresh Direct's slogan: "Our food is fresh. Our customers are spoiled."

You might think these four mental glues are obvious slogan-building strategies, and they are. But it's surprising how few slogans use any of these strategies. In my random collection of 266 advertising slogans, I found only 19 that used any of the four strategies. And some of them were silly.

For example, EDS used the slogan "Globalize, informationalize and individualize," since changed to "Expertise. Answers. Results" (which still doesn't have the soul-stirring cadence of "Liberte. Egalite. Fraternite").

The pass-along market
A sticky slogan is only half the battle. If you want your marketing program to be exceptionally effective, your slogan should contain words consumers can use to pass along your brand's message.

As a general rule, more people are influenced by people than are influenced by marketing. So to generate word-of-mouth, it's extremely helpful to put pass-along words into your sticky slogan.

"The ultimate driving machine" encourages people to say, "Buy a BMW; it's a fun car to drive."

But what is a car buyer to think of the latest Saturn campaign, "Rethink"? Who is going to say to a friend or neighbor, "You should rethink Saturn?"

Even worse is Mazda's long-running campaign "Zoom-Zoom." How can anyone put those words into a sentence directed at adults?

Perhaps the best advertising slogan ever written, in terms of the pass-along market, is McDonald's slogan "You deserve a break today."

"Let's go to McDonald's. You deserve a break today." That's music to the ears of mothers everywhere.

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In addition to his monthly AdAge.com column, Al and his daughter and partner Laura Ries host a weekly video report at riesreport.com.