Proof of the capacity of the proposed AWACS sale to cause dreadful developments is that it has awakened the sleeping pedagogue in me. The pedagogue thinks the nation should define its terms, especially those that denote the things it covets, such as "peace" and "moderation."

If "peace" means simply the absence of armed conflict, then peace is a clear-cut concept, but it is a classification that does not classify in a way compatible with common sense. The United States has not known peace in any meaningful sense since the first week of December, 40 years ago. Thus the president's strategic arms proposal (MX, B1 and the rest) should be understood as another maneuver in what John Kennedy called a "long twilight struggle," countering maneuvers of arms by the enemy. The president's proposal--to deploy a new capacity for violence, for the purpose of countering the enemy's capacity--is not war, but it is indicative of a condition closer to war than to peace.

Similarly, Israel has never known a day of peace. Israel has suffered four wars but the intervals between have not been peace. Saudi Arabia, whose "moderation" is cited by proponents of the AWACS sale, is among the foremost contributors to the climate of war and, hence, to the destabilization of the region.

In his letter offering assurances to senators, the president says he would cancel the sale if "the Saudis adopt policies which are disruptive to prospects for stability of the region and detrimental to U.S. national interests." That statement implies that the Saudis have not hitherto adopted such policies. The statement is an example of the deceptions, including self-deceptions, the administration has been driven to in its search for rationalizations of the sale.

The Saudis have relentlessly excoriated the Camp David agreements. They have persistently undermined the peace process. They have financed the transformation of the foremost terrorist organization, the PLO, into a conventional army in Lebanon. They have called (in January) for a "holy war" against Israel. They have vigorously opposed any military bases on the Arabian peninsula and the Gulf (although the Soviet Union has a substantial presence in Syria and South Yemen). They have pressured Oman to be less hospitable to the United States.

They denounced the hostage rescue mission in Iran as "American military aggression." They raised the price of oil more than $20 a barrel between the end of 1978 and the beginning of 1981. Their oil minister recently threatened a $60-a-barrel price if oil companies would not reduce inventories. And they are the hosts of Idi Amin (who is not in Libya, as George Bush charged when reaching for definitive proof of Libya's immoderation).

Worse than what will happen when the president wins or loses is what already has happened: our political language, and hence our capacity for clear thought and sensible action, has been damaged by the administration's need to ascribe moderation to Saudi Arabia. The administration also has manfully, but unconvincingly, celebrated the "stability" of Saudi Arabia, a nation undergoing pell-mell modernization, with low literacy and 75 percent of its labor force consisting of foreigners.

Some defenders of Saudi behavior say the regime is not immoderate, it is just not brave. They say the funds for the PLO are unavoidable "protection" payments. They say the Saudis are too weak and uncertain entirely to resist the radicalism in the region. But if true, that argument undermines the argument in support of Saudi "stability."

There has always been one, but only one, good argument for supporting the sale: the president (as distinguished from his aides, who concocted this misadventure) does not deserve, and the country cannot afford, another blow to the believability of U.S. undertakings. The argument is not "My country-- or my president--right or wrong" (which, as Chesterton said, is like "My mother drunk or sober"). But there are times, and this may be one, when it is more important for the executive to be effective than correct.

The administration should be prepared, if it wins, to issue a statement that is both reassuring and admonitory. It should reassure Israel and should admonish the Saudis not to believe what is, by now, all too easy to believe: that the United States expects no reciprocity for its favors.

When the Senate Foreign Relations Committee was considering the sale, The Post carried a large front-page photo of two of the president's supporters conferring: Sens. Larry Pressler (R-S.D.) and Charles Percy (R-Ill.). The president should wonder about a Middle East policy that depends on the perceptions of Percy, who thinks the PLO's Yasser Arafat is a moderate, and Pressler, who is not famous for constancy on behalf of the president's, or other, foreign policy views.