"I just don't think it's any of our business," Ronald Reagan said when asked -- on Feb. 1, 1980, in Jacksonville, Florida -- what the United States should do to prevent the spread of nuclear weapons. Now he knows better.

For most of last week, the president's main business was dealing with the consequences of Israeli strike against Iraq's nuclear facility. To defuse the trouble, the Reagan administration first condemned Israel, and then suspended delivery of four sophisticiated fighter planes. Other moves may be necessary to allay Arab wrath and promote the reassertion of diplomacy in the Mideast.

Eventually, the White House now concedes, the administration will have to grasp directly the nettle of nuclear proliferation. For the Israeli strike released a series of unanswerable questions that point the way to nuclear anarchy.

If Israel has the right to take out an Iraqi nuclear installation, what prevents similar actions by the Israelis against Egypt? Why shouldn't Arab states strike against the nuclear installation of the Jewish state? And how about other areas of regional tensions?

India has already exploded a nuclear device, and seems to be developing nuclear weapons. Pakistan moves in the same direction. Would the Indians be justified in a preemptive strike against Pakistan? Could Pakistan rightly hit Indian facilities?

South Africa is also apparently on the road to nuclear weapons. Would the neighboring black states be justified in moving to wipe out a South African facility? Should black rulers go for a nuclear capacity of their own? If they did, would South Africa have the right to wipe them out? And what would the United States do if South Africa were to undertake such a strike?

Subduing the anarchy implicit in those questions begins with easing local tensions. The regional powers that have moved toward nuclear weapons bear the costs and the risks because they feel threatned. So diminishing the threat works to ease the pressure to acquire nuclear arms.

In the Mideast, where there is warrant for everybody's fear of everybody else, that consideration applies with special force. Not only does trying to reduce pressure in the area carry a high priority, but an explicit goal of the process should also be the elimination of nuclear weapons from the region -- including those already developed by Israel.

The supply of nuclear materials to countries interested in the peaceful uses of the atom offers a second hold on weapons development. It makes a difference whether suppliers sell highly enriched uranium, as France did to Iraq, or material more difficult to convert to weapon uses. What happens at the back end of the fuel cycle -- where the material is held for reprocessing and possible weapons development, or treated in some neutral facility -- also makes a difference.

Since consumers of nuclear fuel are sensitive to discrimination by suppliers, there is a case for strengthening international organizations. These could then offer incentives to suppliers to ship only the most benign fuel, while consumers could deposit spent fuel for reprocessing at some international facility.

Finally, regional powers most involved in acquiring nuclear weapons are loath to make sacrifices alone. If the United States does not show restraint about blowing up the world, why should France, or India, or South Africa, or Israel? To a degree, at least, the United States can show restraint by engaging itself with the other superpower, Russia, to limit strategic weapons.

Moving in those directions does not come easily to the Reagan administration. Many of its leading figures -- for example, Secretary of Defense Caspar weinberger and Eugene Rostow at the disarmament agency -- seem opposed on principle to an early resumption of talks with Russia on limiting strategic arms.

Other important officials, citing the experience of the Carter administration, believe efforts to control nuclear supplies only affront friendly countries. The assistant secretary of state for science, James Malone, is the co-author of a policy paper that asserts that "the U.S. should make every effort to restore its credibility and reliability as a nuclear supplier."

Furthermore, many of the administration's efforts to rebuild local confidence seem one-sided. At least in the early stages, the very highest officials made statements that engaged this country deeply in regional conflicts. As a result, hawks in hawkish countries tend to overplay their cards. Now restraint has to be urged upon Israel, South Africa, Taiwan and others.

So the road to a non-proliferation policy is steep these days. Indeed, the Reagan administration has nowhere to go but up.