Rowland Evans and Robert Novak, in "An Iranian March Boosts the Saudis" {op-ed, Aug. 24}, have taken the low road in their latest effort to win support for U.S. arms sales to Saudi Arabia. They depict opponents of the proposed $1 billion arms package -- many of whom are strong supporters of Israel -- as ''being in bed'' with Iran's terrorist regime.

In fact, those who are leading the fight against the sale -- people such as Sens. Alan Cranston and Bob Packwood -- have been in the forefront of the effort to counter terrorism and combat Iranian aggression. They understand that sending billions of dollars of sophisticated arms to Saudi Arabia has done little to secure that nation against the real threat coming from Iran: the spread of Islamic fundamentalism and destabilization from within.

Ironically, a reference by Mr. Evans and Mr. Novak to a CIA study indicating a revival of U.S. credibility in the Arab world points up the difference between serious efforts to protect U.S. interests in the Gulf and the counterproductive approach of selling arms to regimes that don't need them and won't use them. The CIA analysis attributes the rise in U.S. stature to the reflagging of Kuwaiti vessels and the U.S. naval presence in the Gulf.

The point should be obvious. When the United States acts like the superpower that it is, protecting its interests in a bold fashion, the smaller states that benefit from a strong America are impressed. When the United States shows itself unwilling to act and instead sells arms to states that don't have a realistic concept of self-defense, that refrain from providing this country with major military cooperation and that are unhelpful in resolving the Arab-Israeli conflict, then U.S. credibility inevitably declines.

Let us continue to construct a serious policy of protecting the Gulf and its oil and not fall back once again on the nonpolicy of selling arms.

KENNETH JACOBSON

Director, Middle Eastern Affairs

Anti-Defamation League of B'nai B'rith

New York