It was the most momentous of constitutional disputes, and it was no abstract lawyers' argument: The disposition of the war-powers controversy could determine whether hundreds of American military men faced the daily prospect of coming under fire.
The dispute posed two fundamental questions: whether the 60-day time limit in the War Powers Resolution constrained President Reagan's use of the Marines in Lebanon, and whether he had the constitutional power to keep them in hostilities without congressional consent.
The congressional interest lay in establishing that the time limit had been triggered and would require the Marines' withdrawal, and also in establishing that the President lacked sole constitutional authority to use the Marines in hostilities.
The President's interests directly opposed those of Congress. His representatives sought to establish that the War Powers Resolution posed no restraint on his warmaking power, and that it lay within his independent constitutional authority to keep the Marines fighting in Lebanon without congressional approval.
The compromise: no presidential acknowledgment that the 60-day time limit is binding, no presidential acknowledgment that statutory authority is constitutionally required - but congressional consent to keep the Marines in hostilities for 18 months, with no guarantee the President would respect even that longer time limit.
Congress drove a hard bargain. One wonders how its leaders emerged from the negotiations without agreeing to apologize for enacting the War Powers Resolution.
The 18-month compromise does nothing to establish the legitimacy of the resolution. It makes occasional reference to the resolution, but it takes no constitutional scholar to recognize those citations as verbal window-dressing. The compromise provides that ''the Congress determines'' that the 60-day time limit became operative Aug. 29. But the resolution obliges the President to make that determination, and there is nothing in the compromise to suggest that the President agrees with Congress as to when - or whether - the time limit was triggered.