During the past year, for the first time since Vietnam, large numbers of American soldiers have fought and died overseas, and United States warships have shelled foreign shores - all without the prior approval of Congress. Clearly, something is radically wrong with the constitutional arrangements designed to preserve popular control over foreign policy by granting warmaking power to a legislature rather than to an individual.
This latest congressional failure to reasssert control over warmaking in part reflects reluctance to challenge a popular president. But two other factors are responsible: Congress has forgotten what a war is. And the War Powers Resolution of 1973, passed in order to restrain the imperial presidency, has unconstitutionally given the executive more warmaking powers than did the Founding Fathers.
The war-powers issue has been complicated by the need for snap decisions created by nuclear weapons, the increase in civil conflicts worldwide, the growing popularity of ''peacekeeping'' operations, and the Orwellian euphemisms of modern politics - ''preemptive strike,'' ''incursion,'' ''cross-border operation.'' Moreover, the constitutional debate that has taken place in Congress over US policy in Lebanon and in Grenada has become mired in artificial semantic confusions created by the War Powers Resolution, and by the October 1983 Lebanon resolution: Were the Marines in Beirut ''peacekeepers'' or participants in ''hostilities''? Is the bombardment of Beirut ''necessary'' to protect the multinational force, or a ''change in the rules of engagement?''
Yet most of the confusion can be clarified by remembering a simple definition of war that has never been surpassed: Clausewitz's dictum that war is a continuation of politics by other means. President Reagan's policies in Grenada anT in Lebanon clearly fit the bill.
The Grenada invasion disoriented congressional liberals, not only because of its success, but because the administration successfully portrayed it as a rescue operation and as a response to an SOS from local states afraid of Cuba. Yet the operation continued well after the rescue's completion. And while the local states' request may have justified the invasion on foreign policy grounds, the decision to respond militarily constituted an act of war, a use of military force to achieve political objectives. This the Constitution prohibits without prior congressional approval, unless the states seeking help are treaty allies, a status requiring Senate approval. None of Grenada's neighbors qualify.
Nor does Lebanon. Congress has tried to assert its warmarking powers by approving the Marines' presence for 18 months beginning last October, but the President insists that military peacekeeping missions are beyond Congress's authority. But the Marines' specific peacekeeping tasks - guarding the Palestinian refugee camps, monitoring the PLO pullout from Beirut, and overseeing the Israeli-Syrian withdrawal agreement - were mooted by events long ago. Since then, the Marines and the naval guns have been used, as President Reagan put it Feb. 8, ''to deter those who seek to influence Lebanon's future by intimidation.''
Supporting any Lebanese faction is a perfectly legitimate goal which a president is entitled to pursue diplomatically and economically. But when he wishes to use military force for any goal, including peacekeeping, and raises the prospect of American deaths and a wider conflict - when he in effect wishes to go to war - the Constitution says he must get prior congressional approval. This stipulation must hold, even if the US participates in a non-United Nations peacekeeping force (since only the UN has the international legal authority to send peacekeepers to Lebanon), even if the enemy's identity is certain, and even if he drives suicide truck bombs rather than tanks.
Yet the War Powers Resolution permits the executive to make war for 60 days. The act's proponents justify this unconstitutional license on pragmatic grounds. But as Lebanon and Grenada have shown, giving Congress the power to halt overseas military operations already under way amounts to giving it a power it is unlikely to use. Congressional approval is needed before the dispatch of military units, before American blood is shed, and before American honor and reliability are put on the line.
Defenders of the resolution also note that even in 1973, most legislators were only too happy to let the executive keep most meaningful warmaking powers. But Congress's spinelessness has made it easier for the US to plunge into dubious and sometimes disastrous ventures without sufficient debate. Finally, both arguments overlook the fact that if Congress wants to alter the Constitution, it must follow the amendment process. It cannot simply legislate a change.
Political courage cannot be manufactured quickly, but a remedy can be identified. Congress should scrap the War Powers Resolution. The legislators should substitute a measure requiring Congress to approve expressly any military operations in support of treaty allies lasting longer than two months barring a formal declaration of war, and to cut off rescue operations in non-allied countries once the rescue has been completed, or within at most 60 days, unless Congress authorizes a change in mission.
Congress can already halt non-rescue operations in support of non-allied countries without the War Powers Resolution. Presidents would retain the authority to respond to nuclear attack, and to repel conventional attacks on American soil or military facilities - the only remaining contingencies that require an instantaneous response.
Such a change would not unduly restrict presidential power. Rather, it would signal reawakened recognition that, except for a handful of situations created by nuclear weapons, a truly democratic government cannot give one man a power as important as the power to make war.