A Falkland lesson on Taiwan?

Argentina's surprise military seizure of the Falkland Islands offered an important lesson regarding Taiwan's security, for anyone who cared to notice. The incident demonstrated once again what may happen when an insecure authoritarian government experiences increasing domestic pressure from its citizens because of protracted human rights abuses and a lagging economy. It may in desperation launch an aggressive campaign elsewhere in an effort to divert attention from internal problems and to rally popular unity behind a patriotic cause.

It is just this example which leads one to wonder what Peking's ambitions may be a few years hence, when the present regime's modernization goals fail to materialize, the country's economic troubles reach crisis levels, and enlightened Chinese exposed to Western liberalism begin to demand government reform. At such time, an aggressive unification crusade directed against Taiwan could offer several redeeming benefits for Peking.

Yet, at this moment, many observers still question the need for continuing United States defense commitments to the people on Taiwan. To place an artificial ceiling on such assistance is neither practical nor wise, even if Peking ''promises'' to pursue its peace offensive against Taiwan peacefully.

Furthermore, such concessions by US officials are unnecessary. There is ample reason to suspect that Peking leaders, for domestic and foreign policy reasons of their own, are already reconciled to a temporary withdrawal of their ambassador from Washington and a ''symbolic'' downgrading of relations with the US for a short time. In this way, Deng Xiaoping could give mainland China the appearance of a more independent position, situated apart from both Washington and Moscow.

That Peking has already decided upon a temporary but highly visible public rupture with Washington can be detected from several policy pronouncements in recent months. Chinese officials spurned cooperation with Washington's economic sanctions in response to the Polish crisis of last December, actually increasing its level of trade with Poland by 30 percent after imposition of martial law. Peking has openly attacked US support for El Salvador, calling for a ''national liberation movement'' to defeat superpower interference in that country. It has warned the Reagan administration against ''providing assistance and making loans , compromises or concessions,'' to its enemy in the south, Vietnam, in view of recent contacts between Washington and Hanoi.

After a hiatus of several years, Peking resumed demands that the US withdraw its armed forces from South Korea which it claims ''impede the relaxation of tension in the Korean peninsula'' and it refused to act as an intermediary between Pyongyang and Washington after the North Korean missile-firing incident last year.

Chinese leaders continue to differ openly with US official policy concerning the Palestinian issue in the Middle East and sanctions against South Africa, among other longstanding differences. And Vice-Premier Deng has restored his application of the term ''hegemonists'' to the US. A recent assertion by one senior US official that ''when it comes down to it, we don't have any contradictions (with Peking) except Taiwan'' seems naive and misleading in the current context.

Should Peking carry out its plans to temporarily downgrade political relations with Washington, it nevertheless will not allow this move to damage more substantive commercial and cultural ties or the fundamental strategic relationship it now enjoys with the US -- all of which benefit China so much. Therefore, it would be a serious mistake indeed for American diplomats to make major concessions now in a futile effort to reverse Peking's preordained decision on a largely cosmetic, diplomatic maneuver.

The US Congress devoted a great deal of conscientious bipartisan effort to the careful drafting of the Taiwan Relations Act in 1979. It is all the more important now to ensure that those thoughtful commitments are not slowly undone by diplomatic maneuvers carried on outside the realm of public scrutiny. Any binding limitations on the level or time frame of future US arms sales are premature and should be subject to congressional hearings and amendment of the Taiwan Relations Act.