Senator Kennedy's rhetoric rests on a simple argument. In New York past Thursday, the candidate spoke perhaps 10,000 words, but it all boils downs to this:

1. As the U.S. enters "the most difficult and turbulent and revolutionary times in its history, the next President must "set before the people the unfinished business of our society" even if it calls for sacrifice--and lead as Roosevelt did, to our "rendezvous with destiny."

2. "If our society is strong at home, we will be respected abroad" and thus serve as an inspiration to freedom all over the globe."

3. Domestic failings have sapped our strength, and yet the Republican leadership remains "frozen in the ice its own indifference," and the G.O.P. candidate claims that "we've over had it so good." Unemployment is high; half our steel capacity is unused. Nixon has fought against a minimum wage of $1.25 an hour, adequate periodical care for the aged, and aid for education.

4. As the government polls show, U.S. Prestige has declined, because we have "given an image of reaching middle age and beginning to fade."

5. Thus, the 1960 election is between those who wish to stand still" and close who believe "it is incumbent upon us as the chief example of freedom to build a strong and vital society."

Rough Riding

While the "New Frontier" is selection invoked as a slogan, the spirit of progress and adventure pervades Kennedy's rhetoric. Again and again in a single speech, the Senator draws applause with an appeal "to help us those this country forward again." Its choice of adjectives--"strong," "vital," "energetic," "vigorous"--would have delighted Theodore Roose veldt. The Rough Rider has reappeared, pale and wan, as the new frontier man. His bugle blast has faded into an earnest call for "a society with purpose, a society with strength."

In his months of presidential campaigning, Kennedy has perfected a set of rhetorical devices fully as clever as Nixon's. Most successful is his incessant portrayal of Republicans as a lot of fat, contented fellows sunk deep in club chairs, ignorant of the challenges we face, utterly unconcerned about social ills.

Caught between a defense of Eisenhower's record and his own vision of the future, Nixon has repeatedly urged that "a platform is not to stand on, but to build on." Ignoring this device, Kennedy, in a similarly fatuous construction, tells cheering crowds, "this country is great, but it can be greater"--as if Nixon thought the U.S. were soon on the decline.

Sneeringly, Kennedy links his opponent to economic failings and advises audiences that a vote for Mr. Nixon is a vote in favor of unemployment, slums, and overcrowded schools. "If you think that $1.25 an hour minimum wage is extreme, if you think that $50 a week is too much," he says, "then Mr. Nixon is your man."

Roosevelt References

Kennedy's campaign seeks strength in the myth of F.D.R. Never a speech goes by without a quote. "In 1986," John Kennedy says, "Franklin Roosevelt said. "Thus generation of Americans has a rendezvous with destiny'." And repeatedly the Senator speaks in Roosevelt's language--of "a government frozen in the ice of its own indifference," or of "setting before the American people the unfinished business of our society."

Using the 'secret' polls on U.S. prestige as an example, Kennedy hints that his opponent is hiding the truth. "I regard our obligation not to please you but to serve you," he says, "and in my judgment, in 1960, a candidate for the Presidency should be willing to give the truth to the people, and the truth is that what we are doing is not good enough."

But more impressive than a candidate's rhetoric is his style of campaigning. On the platform Kennedy is self-assured. He invariably begins with a request for "your support in this campaign," and always gets applause at the outset. Throughout his usually brief, fast-moving speeches, the audience pays close attention. When the Senator jokes, the crowd laughs, easily and spontaneously. When he asks for help to "move this country forward," the people cheer.

In contrast, Nixon is tense, and his phrasing less skillful. Visibly he struggles for dignity, for sincerity, for occasional folksiness. People some times chat to one another during his speech. And when Nixon delivers a punch line, the crowd often hesitates a split second then applauds loudly and nervously, as if each person were afraid the others would stop if he did.

During his public appearances, Nixon wonders whether to grin or to maintain the grim face of a great statesman, whether to strike out directly at young Jack or depend chiefly on the aura of Eisenhower. As he speaks, the G.O.P. candidate works hard to arouse indignation at "dangerously immature" candidates, and to show respect for Ike, the great symbol of national unity and purpose.

In contrast, Kennedy's style is unexcited. As the campaign pressure presumably builds up, the Senator is simply becoming more sure of him self, more confident about ridiculing his opponent. Part of this style is conscious, an effort to use a bandwagon psychology. But part is Kennedy's own self-assurance, born of wealth and social advantage, a Harvard education and a rigorous family tradition.

During one recent speech, a plane flew over, Kennedy looked up and, as if addressing his opponent, said, "Dick, the voters are all down here not up there."

And the most telling moment of the campaign was surely when Nixon offered, piously and ponderously, to drop the off-shore islands issue, if only the Senator would admit he has retreated from his original statement. During Nixon's speech, the television camera picked up a grinning Kennedy.

Again, Nixon sent a telegram to Kennedy, refusing a fifth debate until the Senator had apologized for suggesting that the G.O.P. candidate was afraid to debate him again. When Kennedy was handed this message--it was last Friday in northeastern Pennsylvania--he laughed, as if to say, "What will this two-bit politician do next?"

Confidence Reflected

And yet, though Kennedy's self assurance borders on a kind of arrogance, it adds to the aura of victory that follows the Senator's motorcade. Surely the newsmen covering the candidate are nearly unanimous in predicting--and hoping for--his election. Nearly all the reports coming from the Kennedy press contingent have been wildly enthusiastic about the success of his campaign--an enthusiasm that adds to the bandwagon effect. But this prediction of victory is not fully justified simply on the basis of what the reporters they observe. It is difficult to have a balanced view when covering just one of the candidates--watching only his crowds, hearing his definition of the issues, his selection of the facts.

The more fortunate journalists--particularly the columnists--can shift from one campaign to the other, getting a basis for comparison (and, of course, saving themselves from the boredom of hearing the same basic speech, watching the same gestures for weeks on end). But a considerable group of journalists become closely associated with just one campaign, marking the struggle for objectivity all the more difficult. As one put it, "The whole show becomes an oblong blur."

And certainly the motorcade-style of campaigning is impressive in itself. Usually a police post-car and a sound truck lead the way. Then come a "pool car" for the wire service photographers (for pictures of handshaking and so forth) and the candidate's convertible, in which Kennedy rides along with two or three of the best dignitaries available for the occasion. Burly detectives follow in a patrol car.

Then come the press buses--usually two, sometimes three--carrying an average of 75 newsmen who regularly cover the spectacle. Behind the journalists are the cars of local candidates who, at stops, edge close to the Kennedy coat-tails, grin toothily for the cameramen, and tell the Senator how deeply moving his last speech was.

The crowds who watch his passage and hear his speeches are, in the day, mostly mothers and children, retired folk and the unemployed. Most of the men are at work. Often the cheers are loud, but then one notices a swarm of young boys yelling or adolescent girls swooning. It was a shred man who manufactured the buttons reading "If I were 21, I'd vote for Kennedy." Of course, many people whom the law defines as mature also lend their voices to the emotional outburst, as if Kennedy were a film star, not a candidate for solemn high office.

Often a local official cannot begin his brief introduction before the crowd starts yelling "We want Kennedy, we want Kennedy." And the Senator keeps up the spirit through his speech, especially as he utters again and again his evocative slogan, "move this country forward."

"If you feel that what we are doing now is good enough," Kennedy says, "then Mr. Nixon is your man." He drops his voice. "But if you share my view that we cannot afford to be second in education, in space, in housing, in industrial production, in the kind of society and opportunity we present..." And the cheers drown out the main clause.

If Kennedy wins on next Tuesday, the verbal appeal most responsible will be the sly suggestion that Nixon is self-satisfied, that the U. S. is falling behind, and that young, energetic, resourceful J.F.K. is the man who can "move this country forward again."

No doubt there is a difference between the two candidates, but it is not in their talents for sophistry