The two lethal wars in the last few weeks, in the Falklands and Lebanon, have been a victory not just for the British and the Israelis, but for the arms salesmen. "Both the dust-ups," the private arms dealer Sam Cummings told me this week, in ebullient form, "will affect the international market for years to come." They also provide critical warnings about the dangers of uncontrolled arms sales.

The Falklands war from the start was full of ironies for the British, for Argentina had been a favorite client for British weapons for over a century. Latin America had long been a controversial playground for the arms-sellers; the war between Bolivia and Paraguay in 1932, which stimulated an arms race in the midst of the recession, led to the first attempts to control the private arms trade.

There was a new surge of arms selling to Latin America in the 1960s, which went further when President Nixon relaxed controls in 1973. The British had some reservations, and the last Labor government refused to sell weapons to Chile because of its shocking human rights record; but this boycott only intensified the sales effort toward neighboring Argentina. Many arms-sellers argued that there was no real danger since the Latin Americans were unlikely to go to war with each other, or with any Western country.

The British sold warships and electronics to Argentina over the last three years worth $200 million; they even lent the Argentinians the money with which to buy two destroyers. The British government has relaxed its controls of arms sales since the Conservatives came to power in 1979, and Margaret Thatcher has personally exhorted arms companies to pursue this profitable market. Only a few weeks before the invasion of the Falklands, the British shipped more spare parts for weapons to Argentina.

The Falklands war showed up all the fallacies of "safe" sales of weapons. It was primarily a triumph for French weapons-sellers: the French Exocet missiles, fired by the French Super-Etendard planes, were the greatest danger for the British ships; and the French company Aerospatiale, which makes the Exocets (run by President Mitterrand's brother), is expected to benefit most from the postwar boom.

But the British also found themselves up against missiles, ships, helicopters and radar which they, themselves, had sold; and one fifth of the Exocet components are made in Britain. A recent cartoon showed two British naval officers looking through binoculars off the Falklands: "Is it one of ours--or one of ours?"

The British received many shocks about the efficiency of the Argentinian equipment, while their own Sea Dart missiles proved ineffective, and they could not counter the Exocet. The full facts behind the war are only now emerging; but according to one military expert "it was a very close-run war; if the Argentines had knocked out one of the British aircraft carriers with an Exocet, they would have won."

There will certainly be many angry questions, now that the war has been won, about past British arms- selling policy. By a preposterous coincidence the British army will stage today its regular arms-selling fair at Aldershot, where British companies show off their weapons to foreign buyers. For the last few years, Aldershot Fair has been a prime target for protestors against the arms trade; this week they will have much more effective political ammunition.

The Israeli invasion of Lebanon has raised questions about arms selling of a different kind: for the Middle East has long been the battleground for weapons supplied by the superpowers to their client states.

The humiliation of the PLO and Syria provides a challenge to Moscow to step up their support with more sophisticated weapons, while the Israelis will certainly be calling for more weapons supplies from the United States. And the devastation of Lebanese cities has been a grim reminder that "small conventional wars" are becoming unconventional in the scale of destruction.

There is little doubt among arms dealers that these wars will provide a major boost for the arms trade. Only recently defense experts were predicting that arms sales to the Third World were getting close to saturation point; but now the scope looks far greater. The Argentinians are already ordering replacements for their losses, while other Latin Americans are determined to modernize their arsenals in the light of the Falklands.

European and American companies see exciting new prospects after a war that provided a classic demonstration for their wares: "We've been watching the Falklands war with intense interest," I was told by an executive from Fiat (which is now hoping to make more weapons to compensate for the slump in cars). "There's no doubt that it will open up new opportunities." The success of the sea-skimming missiles and the vulnerability of aluminum ships may lead to a revision of all naval programs, making existing fleets and arsenals out of date.

The future begins to look ominously like the arms spree of the '30s, and the most ominous resemblance is that the hectic arms-selling coincides with a world recession.

Marxists have always contended that capitalism needs the arms industry to maintain its profits and plants through recessions. Today it is clear that communist countries are equally addicted to arms- selling, whether for political or commercial motives; but it is certainly true that Western companies have been heavily pressed to step up their arms sales in the recent recession. "The great thing about making weapons compared to making cars," as one arms dealer explained to me recently, "is that they're always getting outdated or used up: there's infinite scope for expansion."

The Western nations already saw the dangers of unrestricted arms sales in Iran, where the shah's vast purchases distorted the whole economy of his country, and the weapons were then inherited by the Khomeini regime. But the Falklands war provides a more straightforward example of the most obvious danger--that the weapons may be used against the country that sold them.

And the coming arms boom threatens to impoverish Third World countries still further, depriving them of the productive resources they desperately need. The recent reports of the Palme commission on disarmament (whose members included Cyrus Vance and David Owen) drew attention to the far greater spending on sophisticated weapons by developing countries, which already accounts for a quarter of the world's military expenditure.

"It is a terrible irony," as Willy Brandt wrote in his report on North-South problems two years ago, "that the most dynamic and rapid transfer of highly sophisticated equipment and technology from rich to poor countries has been in the machinery of death."

Is there a chance that these last two wars will induce the Western countries to take more serious steps to limit their contest to sell arms? The Falklands war did produce a temporary agreement to stop selling arms to Argentina by the Europeans including--remarkably enough--the French. And the British Labor Party, led by Michael Foot, has launched a new campaign to stop the "obscene traffic in arms."

Any effective restraints of the new wave of arms-selling will call for the kind of international agreement that is at a discount in the present mood of nationalism and economic insecurity-- whether in advanced or developing countries. But unless some immediate steps are taken, the gleeful predictions of Marxists may begin to look more plausible. The Western nations, as they try to escape from their recession by selling more weapons, could end up destroying themselves.