The curious game of three-corner catch among politicians, the press, and the people of New Hampshire was in full swing this weekend as the Granite State geared up for the 1980 presidential election.

With only 511 shopping days left until the presidential primary here, three men who may or may not be in the market for votes traveled here to woo political leaders and get their names in the local papers.

The big news was Sen. Edward M. Kennedy (D-Mass.), who came here Saturday to make a rip-snorting keynote address before the state Democratic convention.

As Kennedy knew it would, his journey to this state, which is already charged with presidential fever, prompted countless queries about his own ambitions. The senator neatly left all the questions unanswered.

The Republicans countered at their own state convention yesterday with another big-name keynoter, Rep. Jack Kemp (R-N.Y.), the youthful champion of the GOP's tax-cutting legislation.

Although Kemp has had less experience than Kennedy at dodging questions about his plans, he showed considerable skill in the art of denying presidential ambitions without ever closing the door completely.

While Kemp and Kennedy were entertaining party leaders, Sen. Bob Dole (R-Kan.) was campaigning among rank-and-file voters. Although Dole was snubbed by Republican Gov. Meldrim Thomson, he received a warm reception while campaigning.

The activities of all three men, particularly Kennedy, were covered thoroughly by a swarm of political reporters.

"It's ridiculous for them to start 1980 this early," said one reporter. "But if they didn't, we might all be out of work."

It would be unfair to identify the reporter by name because he was, after all, only joking. Or maybe half-joking.

Watching all this with amusement were the voters here, who clearly relish their state's disproportionate importance in presidential politics.

"For us, it's kind of a sporting event," said Don McFarland, a Democratic convention delegate from North Swanney.

The sport of it all seemed to explain the "Ted 1980" buttons and "Kennedy for President" banners that spread like a contagious rash among delegates to the Democrats' convention.

"It's always fund to throw a scare at an incumbent president," said Chris Spyrous, the Democratic leader of the state House. "This Kennedy stuff is just a way to play around with Jimmy Carter."

Kennedy seemed to enjoy his ongoing game of cat and mouse with reporters.

When his plane landed here Saturday morning, Kennedy saw CBS News' Roger Mudd waiting on the runway. "Oh Jesus, there's Mudd," the senator said with a rueful smile. "He always asks the same question."

Kennedy was one step off the plane when Mudd asked it.

"Senator, are you a candidate for president?"

"Well," Kennedy replied, "it's real nice to be back in New Hampshire."

Mudd persisted, "Will you say that you are not a candidate?"

"Well," Kennedy answered, "it's real nice to be back in New Hampshire."

At the convention, Kennedy energized the delegates with a rousing partisan address that offered unstinting praise of all Democrats, including Jimmy Carter, and harsh criticism of Republications.

The GOP responded in even stronger terms yesterday. "They had a speaker at the Democratic convention here," said state chairman Gerald Carmen, (who) if he'd driven a car would have had trouble getting over the bridge."

"Ford pardoned Nixon. The press has pardoned Kennedy," Carmen shouted.

Kemp's invitation to address the Republican convention was something of a coup for such a newcomer to national recognition, even though he was asked only after Gerald R. Ford and Ronald Reagan had both sent regrets. Some party members thought the choice of Kemp indicated that Carmen may be looking favorably on a possible Kemp for president effort.

Kemp gave his standard speech, which matched Kennedy's for partisan fervor. "Clearly, we are on offense this year," the ex-football player said, "and clearly the Democrats are on defense."

Still, the congressman was never quite able to transmit his own enthusiasm to the rather decorous crowd - except when he announced the score of the Boston Red Sox game.

Dole, making his sixth visit here this year, was scheduled to attend a breakfast with Gov. Thomson here yesterday. Dole showed up. Thomson never did. The governor is a Reagan man, and is angry at Dole for supporting the District of Columbia's right to representation in Congress.

Dole did better yesterday afternoon at country fair in Deerfield. A large proportion of the fairgoers recognized him immediately, and people chased after him to wish him well in 1980.

It seemed clear that Dole has not lost the recognition he gained as Ford's running mate in 1976. Dole noted that the contacts he made in that campaign are "the best thing I've got going for me for 1980."

Asked whether he had come to New Hampshire as an observer, a possible candidate or a probable candidate, Dole said the third label was most apt.