USSR's conventional lead requires nuclear arms, says W"orner

West German Defense Minister Manfred W"orner says his government supports main United States arms control positions - with qualifications. The centerpiece of US arms proposals is an offer to cut strategic nuclear arsenals by 50 percent, with sublimits on particular weapons. Such a cut would be a good thing says Mr. W"orner, in Washington for post-Iceland consultations.

But in a world with fewer nuclear weapons, motorized rifle divisions and fighter-bombers take on correspondingly greater importance. So W"orner says deep reductions in nuclear forces must go hand in hand with steps to redress the Soviet Union's lead over NATO in conventional forces.

``It is not that we want to block nuclear disarmament. It is only that we need a certain level of nuclear arms as long as the conventional imbalance is not corrected,'' says W"orner.

The US ``zero option'' would remove all intermediate-range nuclear forces from Europe. West Germany supports this position, but only if it includes restraints on short-range nuclear missiles, an area in which the Soviet Union far surpasses the West.

``It would be unacceptable to leave the shorter-range systems unlimited,'' W"orner explains.

Although the German government supports the zero option, it remains controversial in Europe. On Nov. 17, NATO's deputy commander, German Gen. Hans-Joachim Mack, said that US medium-range missiles based in Europe were of ``paramount importance.''

One arms proposal that W"orner declines to support is the declared US interest in reducing nuclear ballistic missiles to zero after 10 years. The effects of such a move are being studied in his country, he said.

Europeans, feeling the US nuclear umbrella is the main guaranty of their security, tend to become nervous when a ballistic missile ban is mentioned.

British Prime Minister Margaret Thatcher, visiting Washington last week, said that a missile ban was in fact no longer a US goal. But White House spokesman Larry Speakes yesterday reiterated that it is - but that it is closely linked to conventional-force reductions such as those that concern W"orner.

``It's obvious there would have to be a balance between US and Soviet conventional forces. There's no balance now,'' Mr. Speakes said.

W"orner feels the conventional imbalance cannot be changed by coming at it from the other direction and building up NATO forces. His own country, he points out, has already taken the politically dangerous step of lengthening draftees' terms of service to keep army manpower up, and that increased expenditures on hardware are impossible all across the alliance.

Keeping the gap from getting any wider, he says, is the most that can be done.

``There is no hope of correcting the imbalance by increasing armaments over the next 10 years,'' he says.

In the wake of the Iceland minisummit, the Soviet government has made yet another concerted effort to woo the West European public to its point of view on arms issues. W"orner claims the wooing has had little effect; if anything, Iceland is seen in Germany as a victory for President Reagan.

But reports that the two superpower leaders discussed not only elimination of ballistic missiles but complete elimination of strategic nuclear arsenals did cause consternation in West European governments, W"orner admits. ``To declare elimination of nuclear weapons a long-term goal is one thing. To bring proposals to the negotiating table is another.''