By the time a cause gets honored with a stamp, it is usually in trouble.

The bighorn sheep, mental health, blood donation and the Olympics are a few of the movements that have been ensconced on U.S. postage stamps lately. But now comes a cause that even more endangered, even more poignant than the rest:

The doomed art of letter writing.

This is National Letter Writing Week, a commemoration the Postal Service has reinstituted for the first time since 1965. Fifteen cents will get you your choice of six stamps honoring the uses of the letter.

"Letters Lift Spirits!" says one of the new stamps. "Letters Preserve Memories!" says a second. "Letters Shape Opinions!" says a third. "P.S. Write soon!" urge the others.

Letters are a "treasury of our lives," Postmaster General William F. Bolger told a throng of schoolchildren philatelists and more or less ordinary citizens at Monday's announcement ceremonies. "There are things a letter can do that nothing else can," he said, "and many things it can do more effectively."

The Librarian of Congress, who hosted the ceremonies at the Library, has warned of wider and direr implications. "One of the consequences of the telephone and the Dictaphone," said Daniel Boorstin, "has been to dissolve the difference between the spoken and written word. It's hard to mumble in a letter. It's possible, but it's not as easy as on the telephone." m

Bolger also announced an ad hoc committee of support for Letter Writing Week that includes Helen Gurley Brown, Lee Trevino, Stevie Wonder, James Cagney, E.B. White, Mike Douglas, John Cheever, Darryl Stingley, Edward Teller, William F. Buckley and Captain Kangaroo (not to mention the ubiquitous Rev. Theodore M. Hesburgh).

This is a formable group of role-models, but they may be up against one of history's irreversible currents. A nation that demands "instant-on" TV sets is unlikely to return in a big way to the relaxed pace of the heyday of letter writing.

To make matters worse, the postmaster general and his gang are up against the organized might of the American Telephone and Telegraph Company. Ma Bell, operating on the time-tested theory that whatever is down probably needs kicking, has mounted a multi-million-dollar advertising offensive against excessive letter-writing, especially the business kind.

But the trend was already under way. The volume of mail we Americans ship to one another has not been decreasing. Far from it. The Postal Service estimates it moved a record 100 billion pieces of mail in 1979 -- more than 400 for every man, woman and child in the country.

Of those 100 billion pieces, though, no more than 3.5 billion were personal letters.

Between 1972 and 1977 -- the only period for which such breakdowns are available -- the volume of household-to-household mail (the best measure of our letter writing habits) fell nearly 24 percent, according to the Institute for Social Research's massive "Household Mailstream Study."

Spring, 1919

Zelda Fitzgerald to F. Scott Fitzerald:

Maybe you won't understand this, but sometimes when I miss you most, it's hardest to write -- and you always know when I make myself -- Just the ache of it all -- and I can't tell you. If we were together, you'd feel how strong it is-- you're so sweet when you're melancholy.

The statistical evidence is gloomy -- but no more so than the evidence of everyday experience. What are we supposed to do now, in McLuhan's global village, with all the rigmarole of formal letter writing -- the proper indentations and salutations and closings and so forth -- they taught us in grade school? Anyone who has tried to use the mails to look for employment or settle a problem with a credit-card company knows the long odds against simply getting a response. At best, a letter has become a supplement to the frontal assault over the phone or in person.

Politicians still answer their mail -- using word processors, the Library of Congress and vast armies of staff to give each correspondent the semblance of personal attention. But who else is willing to give even the semblance?

Stevie Wonder to Postmaster General Bolger:

Being unable to see puts me in the unique situation of reading through my sense of touch (my staff has important letters and even fan mail transcribed into Braille for me). Sometimes after a session in the studio, I like to go home and sit alone reading through some of these letters . . . . There is no interruption for me, like when you talk to someone in a room with other people -- it inhibits the person communicating. And it's the same with the telephone -- there is just too much distance and electrical nonsense . . . . Reading letters is a very private thing -- the ideas from someone else travel through my fingers and into my brain. It's all very direct and intense and I'm turned on by intensity.

In a current C&P TV commercial, a boss drops by the desk of a well-organized subordinate named Peabody, and warns him about sending so many letters "when you could be getting more done by Long Distance."

"I'm sorry, sir," says Peabody, "but I feel I have to write things down to get my thoughts organized."

When the boss suggests the compromise of a phone call aided by advance notes, Peabody is ecstatic. "Terrific idea!" he exclaims. "I'll make a note of that."

Another recent TV spot stresses the "hidden costs" of letter writing. At screen center," we see a facsimile business letter, with an innocuous 15-cent stamp attached, while in the upper right-hand corner a tiny cash register obstrusively starts ringing up the bucks. "There's dictating time," says a voice ($1.13 -- Ping!), "typing time" ($2.48 -- bong!), "filing costs ($2.70 -- clang!), "materials" ($2.87 -- dong!), "even mailing costs" ($3.24 -- ting!) and "sorting, sealing, stamping and . . . "postage!" ($4.79 -- zing-a-ling-a-ling!).

It will befits a massive quasi-public agency to engage in verbal fisticuffs with a massive quasi-private one. So the most explicit Postal Service comment to date on the telephone company ads is this, from the latest issue of Postal Life, "the magazine for postal employees": "'Reach out and touch someone,' goes a phone company jingle designed to eliminate one's guilt about running up the phone bill when a letter would do. A more accurate phrase . . . would be, 'Reach out and interrupt someone.'"

National Letter Writing Week is the Postal Service's gentle, upbeat way of saying, "Enough's Enough!" It may prove to be more of a wake than a revival service, but either way the time seems right to assess the corpse.

What was letterwriting to us, anyway? After all, though we aren't writing so many letters as we used to, we aren't building so many stagecoaches or mud huts either. Are we merely witnessing another technological leap up the ladder of efficiency?Is it sheer curmudgeonry to worry about the death of the letter, or do we stand to lose something whose replacements can never fully replace it?

Samuel Taylor Coleridge to his son Derwent:

. . . For you are a big Thought, and take up a great deal of room in your Father's Heart: and his eyes are often full of tears thro' his Love of you, and his Forehead wrinkled from the labor of his Brain, planning to make you good, and wise, and happy. And your Mother has fed and cloathed and taught you . . . and she gave you nourishment out of her own Breasts . . . and she brought you into the world with shocking Pains, which she suffered for you. . . . So it must needs be a horribly wicked thing ever to forget, or wilfully to vex a Father or a Mother, especially a mother.

A letter organizes thoughts and emotions. We write to say what is on our minds, but often we arrive at a message that is different from -- perhaps better than -- what we started with. Because we can speak our full piece without interruption, we tend to hear our own words more fully.

Sally Fitzgerald, the biographer of Flannery O'Connor, says that O'Connor would reply to hostile letters with a soft answer to turn away wrath." In "Eight or Nine Words About Letter Writing," Lewis Carrol advised: "When you have written a letter that you feel may possibly irritate your friend, however necessary you may have felt it to so express yourself, put it aside till the next day." And, "Don't try to have the last word," he said.

Letters were once the quintessential mode of dispensing advice. "One should always think of what one is about," the Earl of Chesterfield wrote his ne'er-do-well son Philip. "When one is learning, one should not think of play; and when one is at play, one should not think of one's learning." Chesterfield also counseled his son to "Pocket all your knowledge with your watch, and never pull it out in company unless desired."

Even 300 years later, we can feel the warm paternal vibrations of the earl's massives.We can also feel, almost as urgently as his son must have felt it, the warm impulse to chuck them in the trash.

4 December 1916

Czarina Alexandra to Czar Nicholas II:

My Very Precious One, Good-bye, sweet Lovy!

"It's great pain to let you go -- worse ever after the hard time we have been living & fighting through. But God who is all love & mercy has let the things take a change for the better, -- just a little more patience & deepest faith in the prayers & help of our Friend -- then all will go well. I am fully convinced that beautiful times are coming for yr. reign & Russia . . .

Although letters can encourage moderation, they can also exercise passion. A letter may not, as a rule, be the ideal launching pad for a romantic sally, but it is a valuable instrument for footnoting and amending a face-to-face presentation of the argument.

The full-blown love letter, now all but extinct, was a domain in which the professional writer had a decided edge over the common wooer.

Mark Twain, in his courting days, was permitted to continue addressing his beloved Olivia only on the condition that he regard her as his "sister." So he proceeded to mount a sustained brotherly correspondence during which he would regularly, and artfully, lapse into fervent expressions of his love, only to check himself with a brutal "But no more of this . . . "

Twain, of course, knew what he was doing (and got the girl). But this was a period when many less expert love-letter writers landed in hot water. Hence the popular dictum for young men with breach-of-promise worries: "Do write and fear no man -- don't write and fear no women!"

A 19th-century British naval officer to a creditor:

I am in receipt of your 'Final Demand' for payment of my account. I have to inform you that my normal practice concerning the settlement of debts is to place all of my bills in a hat once a month, from which I draw out two or three for payment. I have followed this procedure with regard to your bill. However, if I receive another letter from you, Sir, the tone of which I consider to be rude, your bill will not be put in the hat at all."

(Quoted in "Dear Sir, Drop Dead! Hate Mail through the Ages," edited by Donald Carroll)

Through the last century and into this one, it was possible to enter into a whole host of binding commitments through the mail. One could rent an apartment, get a job or buy and sell just about any imaginable product without the slightest need to meet the other party to the transaction.

Above all, letters were the way to learn to write. Great and competent writers alike need a modest format with which to begin. The friends and relatives to whom letters go usually have a low tolerance for pretension or inexactness, and so help teach their correspondents to hone their skills.

Lewis Carroll, surely one of history's most committed letter writers, maintained (and advised us all to maintain) a log of incoming and out-going letters, with a precis of each. He logged 98,721 of them between 1861 and 1889, many to or from the female "child-friends" he cultivated throughout his bachelor's life.

Less fanatical Victorians also produced vast bodies of correspondence, Charles Dickens and Henry James actually burned their letters, yet inadvertantly bequeathed us 11,000 and 12,000 respectively. Theirs was an age when almost any important personage -- literary or non -- left "a cocoon as large as a haystack," as John Jay Chapman put it.

Nowadays, even men of letters no longer write them. A book editor who regularly communicates with such folk reports that if she sends one of them a letter (unless it's John Kenneth Galbraith), she gets a phone call in return.

They don't have time for letters, she explains, because "they're paid to write everything else."

As a model for imitation by the over-committed, here is literary veteran Edmund Wilson's all-purpose letter for declining offers:

Edmund Wilson regrets that it is impossible for him to:

Read manuscripts,

Write articles or books to order,

Write forewords or introductions,

Make statements for publicity purposes,

Do any kind of editorial work,

Judge literary contests,

Give interviews,

Conduct educational courses,

Deliver lectures,

Give talks or make speeches,

Broadcast or appear on television,

Take part in writers' congresses,

Answer questionaires,

Contribute to or take part in symposiums or "panels of any kind,

Contribute manuscripts for sales,

Donate copies of his books to libraries,

Allow his name to be used on letterheads,

Supply personal information about himself,

Supply photographs of himself,

Supply opinions on literary or other subjects.