If Walter Hoving ever does have breakfast at Tiffany's, the chances are that he won't be eating crow. Hoving, the crusty, opinionated 78-year-old head of the famed New York jewelry emporium, has spoken his piece over the years to everybody from Presidents to uppity customers. More often than not, he has had the last word.

When President John F. Kennedy asked Tiffany's to produce a few Lu-cite calendars as Cuban missile crisis mementos for his staff, Hoving's response made Khrushchev seem amiable by comparison. "We don't," he sniffed, "work with Lucite, or any other synthetic material." Furious, Kennedy got the plastic calendars elsewhere, was dissatisfied and humbly asked Tiffany's to do them in silver.

Years earlier, Hoving had bested New York's Mayor Fiorello La Guardia in a battle of one-liners. Angry at Hoving's opposition to rising sales taxes, La Guardia thundered, "We can't turn this city over to a floorwalker!" Hoving's riposte was swift. "After all, Mr. Mayor," he cooed, impaling La Guardia upon his celebrated nickname, "every floorwalker has a little flower in his buttonhole."

Now, perhaps to show that age has not mellowed him, Hoving has plunged into another squabble which is being Photographs by Arthur Schatz called the "tiff at Tiffany's."

It all started when Hoving placed a newspaper ad erroneously attributing 10 right-wing aphorisms to Abraham Lincoln. Apprised of his mistake by Lincoln buffs, Hoving apologized. But Tiffany charge account holder Dona Fowler Kaminsky, a labor negotiator who doesn't share Hoving's conservatism, was not appeased. "I'll think twice," she wrote Hoving, "before I enter Tiffany's again."

"I think you are right," Hoving shot back. "So I'm going to do you a favor. I have closed your account." That may not be the end of it, however. Mrs. Kaminsky wants her account reopened and is seeking help from Congress-woman Bella Abzug.

Hoving remains unawed. From his teakwood-paneled fifth-floor office, he directs Tiffany & Co.'s 894 employees, relishes last year's $2.46 million profit (his income: $190,000) and serenely contemplates his future as "a born-again Christian." ("God runs Tiffany's," he declares, expansively sharing the credit.) A vermeil pin in his lapel says "Try God." He gave Billy Graham 50,000 such pins, now has orders from Graham for 150,000 more, and has raised $130,000 for his favorite charity: the Walter Hoving home for drug-addicted young women.

Noblesse oblige is part of Hoving's Social Register life-style. Son of a Finnish physician and a former Swedish Royal Opera prima donna, he was born in Stockholm and came to the U.S. as a child. Graduating from Brown University, he rose through the executive suites of such retailing giants as Macy's, Montgomery Ward's, Lord & Taylor and Bonwit Teller, and became Tiffany's chairman in 1955. With his second wife, Pauline, Hoving lives in a 16-room apartment a few blocks from the store. His son, Thomas, his equal in chutzpah, is director of the Metropolitan Museum of Art; his daughter, Petrea, also by his first marriage, is an insurance woman in New York with three sons. The elder Hoving's credo for Tiffany's is uncompromising. "What you want to buy is your business," he says. "What we sell is our business."