Pakistan's nuclear bomb program threatens to spark a nuclear arms race with India. However, in its Oct. 21 editorial, The Post seems willing to settle for a complacent "second best" in U.S. efforts to restrain Pakistan.

The Post was more on target in March, when it stated that American efforts to deflect the Pakistanis from a nuclear bomb program have failed dismally because the United States "has never made nonproliferation its first priority." As The Post noted then, this is shortsighted in the extreme, since prevention of nuclear war "overwhelms any other American interests in Pakistan."

American law wisely denies aid to nations that violate nonproliferation safeguards. Unfortunately, Washington's wishy-washy policy on nuclear nonproliferation has convinced Pakistani leaders that they can substitute duplicity for restraint: they can feed nuclear passions at home and still receive massive military aid from America simply by denying the fact of their bomb program.

Pakistan's support for the Afghan rebels was not bought with American aid and will not end because we suspend it. Solidarity with Islam and rivalry with India have been fundamental tenets of Pakistan's political life since its foundation. Aiding the Islamic mujaheddin of Afghanistan against India's ally, the Soviet Union, is not a matter of choice for Pakistan's rulers.

We should hold Pakistan firmly to our nonproliferation law, not make it the only country in the world to receive a waiver from it. We should also expand disincentives for nuclear weapons proliferation by making nations such as Pakistan and India subject to trade and lending sanctions if they carry out a nuclear explosion in the future.

Continued complacency will lead from today's nuclear capabilities to tomorrow's nuclear arsenals, and it risks a South Asian nuclear arms race that could end in catastrophe. By then it would be too late to learn from the repeated mistakes of our weak nonproliferation policy toward Pakistan.

EDWARD J. MARKEY U.S. Representative (D-Mass.) Washington