The one thing for sure is that he doesn't know for sure.But Robert Hill-Murray was not a soldier for 40 years without learning to stand by his guns. He thinks he just might be the man who fed President Kennedy the idea that later became one of his most memorable phrases: "Ask not what your country can do for you; ask what you can do for your country."

Hill-Murray grants that recorded history is not on his side. He is not mentioned in any Kennedy history or biography.He never met the late president, nor worked on his staff, nor was paid by him. Nor can he trace how a phrase he gave Rovert F. Kennedy in 1956 became a ringing inaugural call delivered from the Capitol steps nearly five years later - if indeed it did.

All Hill-Murray can offer is the similarity between his 1956 phrase and Kennedy's 1961 phrase - as well as accidents of timing and connection that make his claim at least plausible. "It's enough for me to think I planted the seed," he said.

Hill-Murray's phrase, which he personally delivered to Robert F. Kennedy, is drawn from Alexander the Great's inaugural address of 336 B.C.

"And you, trusted few, seek not to benefit from the bounty of war, nor from what your eyes feast upon within this land," said Alexander, in part. "Diligently seek, rather, in your hearts what you, as faithful believers in our cause, can bring to this, our fresh new world's horizon."

The fit is far from exact, as Hill-Murray, now a retired, 82-year-old writer living in Leesburg, Va., acknowledges. But "I personally am disposed to think (the phrase is) the foundation stone on which JFK built," Hill-Murray says.

Kennedy's former aide and historian, Arthur Schlesinger, writes that the spark for JFK's famous phrase "had lain in Kennedy's mind for a long time," before he wrote his inaugural address.

In 1945, according to Schlesinger Kennedy wrote in his private notebook a vaguely similar thought, cribbed from French philosopher Jean-Jacques Rousseau. At two stops during the 1960 campaign, too, Schlsinger reports, Kennedy used phrases in stump speeches remarkably close to his "ask not" inaugural sentence.

But Kennedy might well have borrowed from an 1884 Oliver Wendell Holmes speech (". . . recall what our country has done for each of us, and. . . ask ourselves what we can do for the country in return.") Or perhaps it was from a portion of President Harding's 1916 acceptance speech before the Republican National Convention (". . . we must have a citizenship less concerned about what the government can do for it and more anxious about what it can do for the nation.")

The trouble is that, so far as is known, Kenneddy never footnoted his inaugural address.But although Kennedy was a historian, he was also a man who depended on fresh ideas. Hill-Murray thus argues that, since he furnished Kennedy the freshest version of an admittedly old thought, he might deserve the credit.

The connection between JFK and Hill-Murray came about thanks to an old Kennedy antagonists named Nikita Khrushchev.

Robert Kennedy and Supreme Court Justice William O. Douglas were visiting the Soviet Union in 1956. Khrushchev told them that certain Voice of America broadcast aimed at Moslems living in the USSR were causing trouble. The old shoebanger said he would personally jam any further such VOA broadcasts if the two Americans didn't see to it that they were stopped.

Kennedy and Douglas did just the opposite. As soon as they arrived back in Washington, they contacted Hill-Murray, then a VOA writer and the author of the programs that were annoying Khrushchev. All his scripts were delivered to Secretary of State John Foster Dulles, who read them, loved them and ordered Hill-Murray to keep them coming.

Robert Kennedy was evidently struck by some of the historical allusions in Hill-Murray's scripts. One day, RJK asked Hill-Murray to prepare a list of 1,000 of his best slogans and phrases. Make them "sad, sullen, explosive, bitter, whatever," Hill-Murray remembers RFK saying. RFK never said why he wanted the list, Hill-Murray says, but "it must have been" that he was already saving strign for his brother.

Hill-Murray compiled his list within three months. Alexander the Great's phrase was among the 1,000. Some weeks later, RFK told Hill-Murray "a closely guarded secret. John F. Kennedy was going to run for president. Robert hoped that I would . . . permit JFK to look over my list of slogans and proverbs for his own use and adaptation.I readily agreed."

Hill-Murray believes JFK may have used more from the list than the Alexander item.

For example, Hill-Murray quoted Lord Robert Clive, an 18th century British commander in India, as saying that his men "shall pay any price, undergo any hardship, rally to any friend any foe" to protect those under the British flag.

In his inaugural, JFK said the U.S. would "pay any price, bear any burden, meet any hardship, support any friend, oppose any foe to assure the survival and the success of liberty."

But is this proof or coincidence? Who really knows? Certainly not Robert Hill-Murray.

"It is all surmise on my part, I grant you," says the former British Armu colonel and Universitu of California professor. Besides, Hill-Murray is caught up these days in writing a volume of adventure stories based on his army service in India. "I am not a man who dwells in the past," Hill-Murray says.

Still, he says he is "proud, oh, yes. Why shouldn't I be? I gave them good phrases. Best they ever had."