Like George Washington and the cherry tree some stories have a life of their own. No matter how many times they are refuted, they are repeated, as if given perpetual care in a prosperous cemetery.

Ranking high on any list of canards is the claim that Harry L. Hopkins once explained the New Deal philosophy as "spend and spend, tax and tax, elect and elect." Since President Reagan's arrival in Washington, I have been expecting a conservative Republican to trot it out again, and my wait has not been in vain.

R. Emmett Tyrrell Jr. ("Party of the Big Heart," June 8) presented these sentiments as the quintessence of liberal Democratic philosophy and "the real reason" for Democratic opposition to the Reagan budget and tax policies. Tyrrell embroiders the story by writting that Hopkins "apprised FDR of the usefulness of the formula 'spend and spend, tax and tax, elect and elect.'"

The problem is that Hopkins vehemently denied having made the statement, and none of the witnesses who were said to have heard his remarks would confirm them.

The story first surfaced in September 1938, in a column by Frank R. Kent, a rabid anti-New Dealer, in the Baltimore Sun and other newspapers and was attributed to unnamed sources. It was picked up by Arthur Krock of the New York Times and by columnist Joseph Alsop and Robert Kinter, who said it was "probably apocryphal."

"I deny the whol works and the whole implication of it," Hopkins protested, but his denials never caught up with the charge.

As head of the WPA, which was funneling billions of dollars in relief funds to the destitute in the wake of the Depression, and one of Roosevelt's closest advisers, Hopkins was regarded suspiciously by conservatives. They seized on the alleged remark as a concise statement of everything they hated about the New Deal.

In January 1939, Hopkins was nominated as secretary of commerce and appeared before the Senate Commerce Committee for confirmation and to deny again the doctrine attributed to him. Kent, Krock and Alsop were requested to appear to testify and cloaked themselves in journalistic immunity when questioned about the anonymous source.

Kent, the only one who claimed to have spoken directly to the source, did not even testify in person but sent the committee a letter in which he worte: "I was first told of the remark in New York by a friend of Hopkins who is also a friend of mine. It was repeated with a good deal of emphasis as part of a conversation that occurred between Hopkins and this mutual friend in August [1938] at one of the New York race tracks. This friend is a man of reputation and standing."

Krock acknowledged he had not spoken to the source or to Hopkins but had printed the remark because it "seemed to me a concentrated gem of Mr. Hopkins' philosophy . . . a most logical statement, it seemed to me, of what Mr. Hopkins might have said."

Robert E. Sherwood, in his biography of Hopkins, later identified the source as Max Gordon, a Broadway producer. Sherwood said that Gordon, Heywood Broun, the columnist, and Daniel Arnstein, a transportation expert, met Hopkins at the Empire Race Track in New York one summer afternoon in 1938. Broun and Arnstein could not recall Hopkins' having made the "spend and spend" remark or any other statement worthy of quotation.

As for Gordon, he acknowldeged that Hopkins did not say the words attributed to him, but told Sherwood, "That's what he meant!"

And that's how legends begin.