A treaty from the past: The signing of the Start 2 accord will complete an old agenda, but the post-Cold War world needs a different approach, argues Lawrence Freedman

The weekend meeting between Presidents Bush and Yeltsin has a certain poignancy. The two leaders are to sign a second strategic arms reduction treaty (Start 2), which will see strategic nuclear warheads cut to about one-third of current levels within 10 years, and the elimination of monster intercontinental ballistic missiles with nose-cones packed with warheads, each equivalent to a few million tons of TNT. With those signatures old-style arms control will have run its course.

Not so long ago such a treaty would have prompted headlines proclaiming 'a great step forward for peace' and pages of optimistic analysis. Today, the treaty seems almost irrelevant. Its value resides less in the detailed provisions than in the larger political consequences, the least of which is President Bush's desire to leave office with a modest diplomatic triumph.

More significant is his attempt to help President Yeltsin avoid lame-duck status of his own. Start 2 will allow him to demonstrate that he is still of sufficient stature to do deals with the Americans. It will be the only traditional arms control agreement to bear Yeltsin's imprint. Hence, perhaps, his typically hyperbolic claim that it is the 'document of the century'. For him that may be true.

The treaty itself is a fitting conclusion to the Bush administration: a modest half-measure that concludes business left over from an old agenda. It ends a negotiating process stretching back almost a quarter of a century to Lyndon Johnson and Leonid Brezhnev. It originated in fear of a superpower arms race. A technological momentum - with precision guidance upon hardened silos, multiple warheads upon anti-missile interceptors - seemed almost by itself to be threatening the international balance. Its morbid logic was captured by the idea of 'overkill' - such a superfluity of weapons that the world could be devastated many times over.

Strategic arms negotiation was designed to establish controls over numbers and technical innovation. Until recently it was a tortuous and not very fruitful process. Even the central achievement of Start 2 will be to reduce warhead numbers by the end of this century only to the levels of 30 years earlier - because the start of the process coincided with the development of missiles with multiple warheads.

Progress was always governed by the overall state of superpower relations. When they were poor, which was as often as not, the main preoccupation was with ensuring that any deals could be properly verified. It was thus an exercise that gave the diplomatic equivalents of accountants and their legal experts years of gainful employment to produce documents of extraordinary length and complexity. This process really concluded with the 1991 Start 1 treaty, which provided definitions and precedents upon which the latest effort could build.

The last-minute hitches addressed in the past few days - over where the Russians can use silos designed for their monster SS-18 for the smaller SS-25, and whether the SS-19 may continue with one warhead rather than six - reflect old concerns about a 'breakout', in which one side would be able to gain a decisive strategic advantage by clever cheating. The Americans have given ground on these questions partly in return for a concession on the transfer of weapons from obsolete B-52 bombers to new B-1s, but largely because nobody considers the old breakout scenarios to be serious any more.

The immediate objective of Start 2 is to help Mr Yeltsin survive his internal battles, because otherwise longer-term disarmament benefits are unlikely to materialise. Success cannot be guaranteed. The disarmament process does not excite most Russians, who are more anxious about their economic conditions, while it is unpopular with senior military officers. Even many moderates are becoming suspicious that, while they are dancing to a US arms control tune, Ukraine is preparing a 'breakout' of its own.

Part of the deal with Start 1 was that Ukraine would become a non-nuclear state. Now this looks less certain. But if Ukraine cannot be prevailed upon to honour its past pledges, then the whole Start process could be used by Yeltsin's opponents to show how the West has forced Russia to lower its guard and given precious little in return.

The centrality of this issue reveals a fundamental problem with the old arms control approach, which was geared to establishing a superpower 'military balance'. No one would now pretend, as was once the case, that equality in nuclear inventories, at whatever level, represents equality in international political muscle.

Obviously it is better that the United States and Russia each has 3,000 warheads rather than 15,000. But if Ukraine sustains a small arsenal or Russia descends into chaos, the number of weapons in such a turbulent region will still seem dangerously large. The end of the Cold War meant that great powers were no longer being propelled towards an apocalyptic third world war via a classic arms race. This was the good news. The bad news, and the threats to stability, lay in the negative consequences of the collapse of Communism, such as the revival of ethnic conflicts in conditions

of general social and economic disorganisation.

Start reflects a world that could be governed from the top down, when a 'summit' involving the leaders of a few great powers could make the difference between peace and war, and decisions might be taken on the basis of calculations of relative military strength. Now, the international political system is being recreated from the bottom up, through local struggles for power that set boundaries of territorial domination and precedents for political behaviour.

The main risk of nuclear detonation now derives from the possibility that Cold War weaponry might be caught up in these struggles. Even while Lawrence Eagleburger, acting Secretary of State, was adding the final touches to the treaty, Bosnia was reaching boiling point and Israeli-Palestinian relations were going backwards.

The challenge for the great - and once-great - powers lies less in regulating their own military arsenals, now that they have no reason to expect war with each other, than in preventing these lesser struggles getting out of hand. If arms control is needed now, it is to deal with small arms and mortars as much as with intercontinental missiles and bombers; to gain agreement from militia commanders as much as from superpower generals. It must worry less about verifying compliance with orderly disarmament than about enforcing demands made on local groups that violate the basic principles of international law.