The battle to win the hearts and minds of United States allies over deployment of nuclear missiles intensified this week on at least three fronts. Ronald Reagan offered to meet with Soviet leader Yuri Andropov to ban such weapons ''from the face of the earth.''
Secretary of State George Shultz tried to assure Japanese leaders that any US-Soviet agreement on nuclear missiles in Europe would not come at the expense of Japan, which fears that under some scenarios the Soviet Union could move more missiles to its Eastern front.
Almost simultaneously, the debate within the Atlantic alliance heightened with the release (in Bonn, London, and Washington) of a report by American and European experts challenging NATO's current nuclear policy.
This report, published by the Union of Concerned Scientists (UCS), warns that the alliance's strategy of ''flexible response'' - which includes the possible use of nuclear weapons in the face of a conventional attack from the Warsaw Pact - ''could, with unacceptably high probability, culminate in the ultimate disaster of a strategic nuclear exchange.''
With reform of NATO forces and a modest increase in defense spending by the allies, say these analysts (many of them former senior military officers), a sufficient conventional deterrent could be built allowing the alliance to adopt a ''no first use'' policy. This would strengthen the alliance, sharply reduce the likelihood of nuclear war, and lead to a better climate for eventual arms reductions, the report concludes.
These critics thus agree with recent pronouncements from the NATO commander, Gen. Bernard Rogers, and others who urge a beefed-up allied conventional force. But they take sharp issue with US and NATO policy as outlined most recently in Secretary of Defense Weinberger's budget message to Congress.
''The danger of a 'no first use' pledge remains that it could increase the chances of war and thus increase the chances of nuclear conflict,'' Mr. Weinberger warns.
US officials usually compare US and Soviet force levels, concluding that the Soviet Union is far stronger and that the US not only must spend much more but must continue a doctrine of possibly initiating nuclear war.
This week's report (as well as earlier conclusions by other analysts) states that ''the (Warsaw) Pact's numbers would be judged borderline to inadequate for a Central European offensive.''
Among the reasons cited: relative balance when all of Warsaw Pact and NATO forces are tallied up; questionable allegiance and performance of Eastern European forces if asked to fight for Soviet goals; Western technological advantages; likelihood of France (which is not part of NATO's command structure) joining the alliance in time of war.
''Too much of the discussion on the military balance has been simple-minded talk about how many troops and tanks the Soviets have,'' said retired US Vice-Adm. John Marshall Lee, director of the UCS study.
At the same time, however, this study notes certain weaknesses in NATO forces and changes needed to declare ''no first use'' of nuclear weapons.
These include: stepping up the program of storing US military equipment in Europe; building field fortifications and obstacles along the East-West frontier to hinder possible attack; increasing NATO stockpiles of supplies, ammunition, and fuel from 15 days to 30 and eventually 45 days.
The total cost of these improvements, it is estimated, would be less than $ 100 billion over six years, or about a 2 percent annual increase (not counting inflation) in defense spending by the allies.
But it is not without serious political hurdles. Building tank traps around their villages is a frightening prospect. The French and British have been moving toward greater reliance on nuclear weapons. And more defense spending in tough times is as unpalatable in Europe as in the US.