The Nuclear Regulatory Commission's resounding vote of no-confidence this week in the international system of safeguards on which trade in nuclear technology is premised is but the latest in a series of events and policy shifts that has all but wiped out American non-proliferation policy.

As one who once had a hand in helping to formulate that policy during part of the Carter administration, I have watched with awe the rapidity with which the dismantling has taken place.

The erosion began last spring in a close vote by the Senate Foreign Relations Committee approving an administration request to permit a large new assistance program for Pakistan by waiving the law that prohibits assistance to a country trying to make nuclear weapons. The vote attracted little attention at the time, yet it was a significant milestone: in the first test of its own sanctions against nuclear proliferation, the United States was choosing to ignore them.

By the time the waiver reached the Senate floor a few weeks ago, there was no remaining doubt that Pakistan is aggressively pursuing every possible technical route to building a bomb. It may be ready to stage a nuclear explosion in one year.

Nevertheless, the full Senate chose not to vote on the wisdom of the waiver. Sen. John Glenn (D-Ohio), trying to redraw the line he had helped write into law a few years ago, offered an amendment requiring termination of American aid if Pakistan went all the way and actually detonated a nuclear bomb. But the message that was conveyed that evening to Pakistan, and who knows how many other interested governments, was not that the amendment had passed--which it had, just-- but rather that nearly half the Senate -- 45 members--had voted against it, in the name of preserving "flexibility" for the president. The flexibility in this case is the flexibility to do nothing--as this country did when India exploded its bomb in 1974.

Meanwhile Israel had bombed Iraq's research reactor. The International Atomic Energy Agency's response was not to investigate why Iraq, despite having no commercial nuclear facilities, was stockpiling hundreds of tons of uranium ore. Nor did it or any other group consider intelligence findings that Iraq was indeed pursuing a nuclear capability, despite having renounced the right to do so by signing the Non-Proliferation Treaty. Instead the IAEA called on its members to offer Iraq "emergency assistance" to rebuild the destroyed reactor.

France, Iraq's original supplier, responded. Discussions between France and Iraq have been under way since last summer. American officials are apparently not privy to the terms being negotiated, especially whether the new reactor will be as inexplicably large for its asserted "research" purpose as the old one was, or whether this time France will insist that the reactor not be fueled with highly enriched, weapons-usable uranium.

France's recent agreement with South Africa does not offer much ground for optimism. The United States has been trying for years to get South Africa to accept safeguards on its nuclear facilities. Its leverage was the supply of fuel rods for South Africa's first power reactors scheduled for completion next year. But American law requires that South Africa first accept safeguards. Suddenly, in mid- November, it was announced that the reactor would be loaded on schedule with fuel rods made in France, and without safeguards. The action took American officials completely by surprise, cutting the ground out from under the U.S. government's position.

A few years ago, the nuclear supplier nations agreed to an informal moratorium on the transfer of reprocessing and enrichment plants--facilities that produce material that is directly usable in bombs. This year, for the first time since that agreement, a non-nuclear weapons state--Mexico --has invited bids for the construction of power reactors and let it be known that it wants "advanced technology"--enrichment and reprocessing--to be part of the deal. The suppliers' responses will be a major test of how much, or how little, is left of the will to slow nuclear proliferation. The outlook is clouded by the administration's recently announced willingness to transfer classified enrichment technology to Australia, making it all the harder to say no to others.

Several other thresholds have been quietly crossed. In extending an agreement that allows U.S.-supplied fuel to be reprocessed in Japan's pilot reprocessing plant, the administration, without prior congressional consultation, dropped two key provisions of earlier versions. One of these dealt with whether reprocessing plants, because they provide direct access to weapons-usable materials, can ever be effectively safeguarded. The other retained U.S. control over Japan's use of the separated plutonium.

U.S. negotiators, unable to find acceptable conditions for ending nuclear cooperation with India, are reportedly considering major concessions. The United States wants international safeguards to continue to be applied to the used fuel (containing more than a ton of plutonium) it has supplied to India over 18 years. India has refused, and is reportedly considering a unilateral renunciation of the agreement and its attendant safeguards. To avoid that damaging precedent U.S. negotiators may allow India to reprocess the U.S.--supplied fuel.

The Reagan administration let it be known from the outset that it planned a dramatic "shift in emphasis" from the Carter non-proliferation policy. It would emphasize American leverage as a "reliable nuclear supplier" rather than trying to restrict access to sensitive nuclear technologies. But leverage is only leverage if one is prepared to use it. The administration's easy acceptance of Pakistan's nuclear bomb program and many subsequent decisions signaled clearly that it was more interested in encouraging nuclear trade. The message was picked up not only by potential proliferators but also by other suppliers-- France, especially--that had reluctantly gone along with earlier U.S. insistence on a tough non-proliferation policy. Congress, overwhelmed with other concerns, failed to respond. The result has been a frighteningly swift unraveling of the containment net that had been slowly stitched together in the seven years since India's nuclear explosion shocked the world. No one knows where it will end or what it will now take to stop the process.