IT'S HARD NOW to remember the Great Arms-Control Panic of 1984. The Geneva arms talks had collapsed a few months earlier, and some prominent Americans were talking of nuclear war as a real and imminent danger. The future of humanity seemed to hinge on the minutiae of disarmament.

The hot political book that year was Strobe Talbott's "Deadly Gambits," which tried to make the world's dullest subject -- the bureacratic politics of arms control -- sound interesting. Actually, "Deadly Gambits" was light reading that season. Truly serious readers were devouring books with titles like "Weapons and Hope," "The Evolution of Nuclear Strategy" and "The Command and Control of Nuclear Forces."

The Great Panic has eased for a simple reason: Arms control is back, bringing with it The Great Panacea. Last week, the United States and the Soviet Union moved to the verge of signing an agreement banning intermediate-range nuclear forces (known to the jargon-mongers as "INF"). The recent details of the INF talks have eluded all but the most dogged readers of "Arms Control Today," but never mind. Arms control is supposed to be dull. It was the absence of this arcane and reassuringly incomprehensible process of negotiation that bothered people in 1984. Now that the bean-counters are back at work in Geneva, we can relax.

But before the hoopla of treaty-signing and summitry begins, it may be useful to examine several of the less-obvious implications of the agreement that President Reagan will sign this fall. These details don't diminish in any way the value of the INF accord, which is an important achievement and one that enhances American security. But they do show some of the hidden dynamics at work in U.S.-Soviet relations.

Arms control is here to stay. The INF agreement means that the process of Soviet-American negotiation over nuclear weapons has survived its harshest test -- and emerged intact. Arms control is now, indisputably, a permanent feature of the terrain of Soviet-American relations. Future administrations may bridle at this political fact of life -- just as some members of the Reagan administration initially did -- but they aren't likely to change it. After all, once the INF agreement is signed, arms control will carry the blessing of Ronald Reagan himself.

How rapidly things have changed. Three years ago, former national security adviser Zbigniew Brzezinki could argue: "A very strong case can be made that we've come to the end of the road with traditional arms-control agreements." The process of negotiation seemed so moribund that the head of the Arms Control and Disaramament Agency, Kenneth Adelman, proposed in 1984 that we seek instead "arms control without agreements."

The deep-freeze years taught politicians that arms-control is politically essential, whatever the strategists may think. When the Soviet Union walked away from the bargaining table in 1983, the Reagan administration faced a political crisis. Arms control remained an emotional issue in the 1984 presidential election, and Congress threatened to cut spending for strategic weapons. The political crisis ended only when the Soviets returned. For politicians, the lessons were obvious: No candidate from either party is likely to be elected president (or dogcatcher, for that matter) if he opposes arms control; and Congress won't spend money for strategic weapons unless there is a simultaneous process to limit such weapons.

For these reasons, arms control is now embedded in our political life; successful governance means, in part, success in limiting nuclear weapons. And that is something worth celebrating.

Moscow won its battle to remove the Pershings. The great mystery of the INF talks is why the Soviet Union fought so hard to reverse American deployment of Pershing II missiles in Germany. The Soviets have tried everything -- from bluster to craven compromise -- to get the Pershings out. Which should give us pause: Any weapon the Soviets dislike so much can't be all bad.

Consider the remarkable sequence of events: First, the Soviets tried to intimidate West Germany into refusing the Pershings; when that failed in late 1983 and the missiles were deployed, the Soviets walked away from the INF and START talks and said they wouldn't return unless the missiles were withdrawn; when that failed, the Soviets said they would resume negotiations with the United States, but only about space weapons; when that failed, the Soviets said they would resume START and INF negotiations, but only if they were linked to a ban on space weapons; when that failed, the Soviets agreed to de-link the talks and reach a separate INF deal, but only one that covered Europe alone; when that failed, the Soviets agreed to a global ban, and when the United States made noises about short-range missiles, the Soviets agreed to ban them, too.

This chain of Soviet concessions demonstrates, in part, the benefits of hard bargaining by the Reagan administration and its Geneva negotiator, Max Kampelman. But it also suggests that, in Soviet eyes at least, the Pershings were immensely valuable for NATO: militarily, as a first-strike weapon that could destroy the Soviet command-and-control system in the opening minutes of a war in Europe; and politically, as a way of linking America more tightly to the defense of Europe. The Soviets, it seems, were willing to pay almost any price to scuttle the Pershings. Sensibly, we demanded that they destroy an equivalent class of weapons, the S-20s.

For NATO, the worst is yet to come. When we remove our Pershing and cruise missiles from Europe, our NATO allies will be left with the same awkward strategic problem that led to their deployment in the first place: the unreliability of America's nuclear umbrella.

By the late 1970s, with arms control in full flower, many European strategists had begun to doubt the credibility of American promises to use nuclear weapons, if necessary, to defend Europe from Soviet attack. The Germans, to put it simply, doubted that America would sacrifice New York to save Bonn.

Comments by American experts seemed to confirm that these fears were justified. The American commitment to respond to a Soviet conventional attack by launching strategic nuclear weapons would be "an act of suicide," wrote Robert McNamara, a former secretary of defense. Similarly, former CIA Director Stansfield Turner wrote in these pages last year: "It's not conceivable that any president would risk the very existence of our nation in order to defend our European allies from a conventional assault . . . . "

The Pershings and cruise missiles were supposed to solve this problem. This new category of weapons would install an additional nuclear "tripwire" in Europe, which would make it more likely that a Soviet attack would lead to nuclear war, and thereby deter the Soviets from launching such an attack.

The problem with the Pershings -- and the reason it makes military sense for the United States to remove them -- is that the tripwire was too tight. Because the Pershing was such a potent first-strike weapon, and so integrated with the defense of Europe, it raised the incentive for the Soviets to strike a pre-emptive nuclear blow themselves.

With the Pershings and cruise missiles gone, Europe will go back to the old leaky and unreliable American umbrella. The answer, all the strategists agree, is for NATO to spend more for conventional defense. But don't hold your breath.

The superpowers have reversed roles in arms control. Moscow's tireless push for an INF agreement, and Washington's wary acceptance, illustrate how far the two nations have moved from their traditional diplomatic roles. These days, under Gorbachev, it's the Soviets who are the initiators in the arms-control dialogue. They're the ones pushing hardest for agreements, and they're the ones who make the key concessions. The Reagan administration, in contrast, plays the stolid role once reserved for the Soviets: watching, waiting, forcing the other side to make the first move.

This role reversal is exactly what some American officials thought was needed. Let the Soviets take the lead and offer the concessions, they argued. The poker-faced American approach may indeed be good negotiating practice. But the growing popularity of Gorbachev in Europe, and Reagan's corresponding decline in the polls, makes one wonder whether a Soviet-style wardrobe is really what Uncle Sam needs in the 1980s.

David Ignatius, an associate editor of The Washington Post, is editor of the Outlook section.