At the Lyndon Johnson-Alexei Kosygin summit at Glassboro, N. J., in 1967, the United States introduced an issue -- strategic defenses -- which remains on the table for the Ronald Reagan-Mikhail Gorbachev summit coming up in Iceland. According to the standard American accounts, Johnson, with the aid of his defense secretary, Robert McNamara, tried to interest Kosygin in a ban on defensive systems, but Kosygin rejected the overture, dealing a rude blow to the SALT process as we know it.

But Anatoly Dobrynin, the long-term Soviet ambassador to the United States, who was at Glassboro, offered a different version to an American before departing for Moscow earlier this year. It makes the disappointment of Glassboro more instructive for events today.

In the winter of 1966-67, the Soviets began getting signals from the administration that it was ready for talks on strategic defense. We now know why: a crude Soviet ABM was being built near Moscow and the Joint Chiefs of Staff were pressing to put deployment of a U.S. ABM (the Army's Nike X) in the budget. McNamara was strongly opposed to this step, but his standing had been affected by his questioning of escalation in Vietnam. He proposed a compromise: to put long-lead ABM items in the budget but not to spend the money while the administration tried for negotiations with Moscow.

Returning from the LBJ Ranch, McNamara talked to the State Department, which began talking with the Russians. He then had a long private meeting with Dobrynin. Dobrynin, according to his own recent account, was impressed. During the preparations for Glassboro, he says, he told Kosygin that McNamara was a genius who would come to Glassboro with important proposals, tables, charts, numbers, to which Kosygin should listen closely.

In fact, McNamara's staff only learned the day before that his proposals would be on the agenda at Glassboro. Overnight, they prepared a talking paper for McNamara, but no charts or slides.

At Glassboro, Johnson talked and talked. There was no hint of a major McNamara briefing. But at lunch, which was attended by numerous Soviet and American officials, Johnson suddenly turned to McNamara: "Bob, why don't you do your thing now. You've got 15 minutes."

The result is well recorded. McNamara lectured Kosygin on the dangers of defense and the merits of offense, talking fast in his usual forceful style.

Kosygin appeared not to understand the lecture. "When I have trouble sleeping nights,'' he said, ''it's because of your offensive missiles, not your defensive missiles." He rejected McNamara's offer to negotiate, and the subject was closed.

Dobrynin now explains that Kosygin thought McNamara wasn't serious. He had been led to expect a full exposition with charts and slides, the work of a genius. Moreover, in the Russian view, Dobrynin indicated, nothing serious is discussed at lunch in front of 20 people who might or might not have been cleared for a full briefing.

It can be argued that McNamara's lunch lecture succeeded in the long run. The two sides moved toward talks in 1968 -- and halted after the Soviet invasion of Czechoslovakia. Finally, the Soviets embraced the principle of mutual reliance on offense in the 1972 treaty limiting ABM systems. Today, in opposing Reagan's Strategic Defense Initiative, the Soviets give us the same lecture on the perils of defense that they heard in 1967.

The failure at Glassboro, nonetheless, was costly. Kosygin's reaction dashed any immediate prospect of talks. Johnson instructed McNamara to proceed with the ABM. McNamara announced deployment of a "thin" ABM against the barely existent Chinese ICBM threat. Under Richard Nixon, the "thin" ABM was expanded to a proposed "thick" system to defend against Soviet ICBM attack. Meanwhile, the United States pushed forward with the technology of independently targeted warheads, MIRVs, to counter the Soviet ABM.

Had Glassboro gone differently, these upward twists in the arms race might have been avoided.

There is also a specific lesson in Dobrynin's story for Reykjavik. At Glassboro, the Russians had expectations for the "serious" part of the agenda and a cultural bias in favor of raising the most serious matters only in the smallest circle. But if the Americans knew of these expectations, they ignored them. Meanwhile, on the American side, whoever led Dobrynin to advise Kosygin that a big briefing was coming was out of touch with Lyndon Johnson's thinking and style. So McNamara's lecture and Kosygin's curt reply set back an initiative in which both had an interest.

One hopes that, 19 years later at Reykjavik, both sides understand each other better than they did at Glassboro.Deborah Shapley is the author of a forthcoming book on Robert McNamara.