Now that Washington's abuzz with schemes to control Middle East weaponry, let's push one arms-control scheme that's straightforward, timely, effective and verifiable: Expand the bilateral ban on intermediate-range nuclear forces - the INF treaty that Ronald Reagan and Mikhail Gorbachev signed in 1987 - into a multilateral treaty that bans Scud-type missiles.

The United Nations was right to impose on Iraq a ban on missiles that threaten the region.Proposing a worldwide treaty would be simple, since treaty language banning land-based ballistic missiles with ranges from approximately 300 miles to 3,400 miles has already been drafted and carried out.

How ludicrous that Iraq and North Korea can legally have Scud missiles while we and the Soviets cannot.

That incongruity would end if U.S. and Soviet envoys introduced a joint treaty banning such missiles at the 39-nation Conference on Disarmament in Geneva.

Americans and Soviets could thereby cooperate on stopping missile proliferation, just as we have on stopping nuclear proliferation.

But this accord would not be discriminatory, unlike the other one: We would not be asking any country to give up anything we and the Soviets hadn't already forgone.

The have-nots wouldn't resent the haves. Everyone would become a have-not.

Such an approach is certainly timely.

Ballistic missiles are spreading like wildfire, and the flow of First World weapons of mass destruction to Third World nations clearly constitutes our gravest security concerns.

Last November Defense Secretary Dick Cheney stated that by the year 2000 "more than two dozen developing nations will have ballistic missiles, 15 of those countries will have the scientific skills to make their own and half of them either have or are near to getting nuclear capability as well."

He said that "30 countries will have chemical weapons and 10 will be able to deploy biological weapons."

These numbers are worse when names are put with them: Libya, North Korea, Iran and Iraq.

Also poised or beginning to produce missiles are Argentina, Brazil, India, Israel, Pakistan and South Africa.

Egypt, Syria and Saudi Arabia may be buying missile technology from China and others.

Many Arab countries would welcome the eradication of Scudlike missiles after having watched them threaten Saudi Arabia nightly.

Ditto for most Israelis after their sleepless Scud-scary nights.

This type of treaty would meet the stiffest resistance from China, which peddles ballistic missiles, and France, which deploys them.

But even if China and France refused to enroll, such a ban would still be valuable. After all, this twosome, along with Israel, has never signed the nuclear non-proliferation treaty, which nonetheless has become the jewel in the crown of arms control.

And if additional states initially refused to sign up, the mere act of the Americans and Soviets promoting this ban would make procuring ballistic missiles wicked rather than wonderful.

Fortunately, such an arms-control agreement could be neatly verified.

The key to any INF-type accord is a ban on missile flight tests - something easily detectable to outsiders and yet mightily restrictive to any hankering states, which would lack confidence in an untested system.

We can, and should, do more than watch the awesome spread of missiles with resignation and small steps.

Parkinson's most perceptive law says success of a policy is measured by the catastrophes that do not ensue.

Here's a rare opportunity - through arms control, no less - to preclude loads of catastrophes.