More than 40 New Hampshire towns have stood up and instructed Leonid Brezhnev and Ronald Reagan to knock off the nuclear arms race. So far, only Antrim (pop. 2,000), a lovely little place in the Monadnock mountains, has done so in the middle of a raging love affair with a U.S. Navy warship.

Antrim, bred-in-the-bone Republican conservative, has a proud patriotic tradition. A plaque set in the boulder at the highest point on Main Street records that "every man except one marched in response to the Lexington alarm."

But last Saturday, at its annual town meeting, Antrim somehow managed to make official its meaningful relationship with the USS Antrim, which everyone is pretty sure carries nuclear missiles, while at the same time voting almost 2 to 1 in favor of a bilateral U.S.-Soviet nuclear weapons freeze.

It was Article 30 on the warrant, the agenda of the town meeting, and it came between an article proposing the relocation of Old Mountain Road and another to allow a restaurant on Main Street to construct a ramp.

Antrim's emotional involvement with the missile frigate came about through an enterprising public relations officer, who wrote to six U.S. towns named Antrim seeking a home-town tie with the ship. Only Antrim, N.H., responded, and three citizens--all members of the Veterans of Foreign Wars--journeyed to Seattle for the commissioning last September. Since then, the romance has blazed.

In the first raptures, the captain of the Antrim, Cmdr. Bill Wright, confided his hope of seeing a New England town meeting. It was a genuine coincidence, both sides thought, that he happened on one at which Antrim took up war and peace.

A banner was stretched across the side of Wayno's supermarket. "Welcome to your town, Capt. Bill," it read. At a welcoming ceremony, Wright presented a ship's flag to the town. Pro-freeze leader Bonnie Achterman, a black-haired mother of three daughters and secretary to the pastor of the Presbyterian church, watched these signs of rising patriotic fever with some apprehension.

She had collected the 10 signatures necessary to put the freeze issue on the warrant at Edmund's hardware store, whose motto is, "If we don't have it, you don't need it."

"They have the flag," Achterman said wistfully of the townspeople during the military welcoming presentation that left several spectators awash.

Thus stirred, the people, with Cmdr. Wright in tow, toiled up the hill to the gymnasium of the elementary school to do the town's and the world's business. Article 10, "to see if the Town will vote to adopt the USS Antrim (FFG20) and heretofore be known as the 'Home Town' of the USS Antrim," produced the first fireworks.

Suddenly, in the back, a stocky, fair-haired woman stood up and introduced herself as Jane Chase. In ringing, trembling tones, she said, "My great-great-great-great grandfather was a colonel in the Revolutionary War. My family has lived at the Butterfield Farm since 1800. I was a flower girl at the dedication of this gymnasium. My husband and I choose to make Antrim our home. I do not choose to have my home town represented to the rest of the world by an instrument of war."

In the gasps that followed, a white-haired man named Pete Wallace rose and riposted in near-apoplectic tones: "My ancestors fought the Indians. They fought in the Revolutionary War, the Civil War, World War I and World War II. I hope they continue to fight in the last of the wars. Let's adopt it."

He was much applauded. Cmdr. Wright, somewhat shaken by this genealogical exchange of fire, said that yes, it was a warship but that the relationship between town and ship was "spiritually uplifting."

The resolution carried overwhelmingly.

Most of the citizens went back down the hill to the Presbyterian church and an excellent homemade lunch. The affable, lionized commander, who had changed out of uniform, had done a tour with a SALT negotiating team and, as a citizen, said he had no quarrel with the freeze. But he decided not to return to the town meeting, because it might be dicey--"You are talking about petitioning my commander in chief."

It was 3 p.m. by the time Article 30 came up. Almost immediately, it sank. An intense, stooped man named Ben Pratt said the Soviets would interpret it as "evidence of divisiveness." The anti-freeze faction in the middle of the hall clapped loudly, and 18-year-old Jeffrey Merrifield called for tabling of the resolution.

Town counsel Lloyd Henderson, not allowed by law to express an opinion, came to the rescue. Other towns, he said in a subliminal appeal to local pride, had voted one way or another. The tabling motion went down by voice vote.

Christopher Burr, a student at Keene State College, said, "We have 40 times overkill . . . This is insanity . . . The only people who can stop it are us."

John Catalini, a high school English teacher, finally braided the two strands of the day:

"It isn't incompatible for us to support the USS Antrim and the nuclear freeze. One has the capacity of bringing peace, through person-to-person contacts, but a nuclear bomb can do only one thing--make war."

A heavyset woman named Virginia Rowhel, speaking passionately, said she would never trust the Soviets for anything and would "rather be dead than Red."

What turned the tide was an amendment offered by airline pilot Pat Webber, who seemed to understand that the anti-freeze people were torn by a feeling that the measure was an affront to Ronald Reagan. A clause asking the president "to continue and intensify his negotiating efforts" split the opposition and, on a ballot vote, the freeze won, 83 to 44.

"Isn't it funny?" asked moderator Robert Flanders, who had presided with near-perfect equanimity. "We voted for and against nuclear weapons in the same day. But that's what town meeting is all about."