In a little-noticed development, the United States has made a ''quantum jump'' (in the words of one West German official) in consulting allies on nuclear weapons policy.
This new cooperation was highlighted Dec. 10 by the report to NATO foreign ministers by Paul Nitze, chief American negotiator at the US-Soviet talks on European nuclear arms control.
So far, the consultation is working far better than anyone might have hoped on the basis of past experience. The NATO alliance was sorely divided over responses to the Soviet invasion of Afghanistan two years ago - and over subsequent shoring up measures in the Mideast, an awkward area outside the classic NATO region.
And even before that, America's first explicit attempt to engage the Europeans in nuclear procurement decisions - the infamous neutron-warhead case - left behind a poisoned relationship between President Carter and West German Chancellor Helmut Schmidt.
This time, it's different. Shock over the post-Afghan dissension has made NATO members work more urgently to pull themselves together. Shock over the bad Carter-Schmidt relations has made Schmidt curb his frequently didactic and acerbic tongue in dealing with President Reagan. Concern about the mushrooming antinuclear movement in Europe has made Washington yield to Schmidt's importunings and enter the European nuclear arms control talks that began in Geneva Nov. 30.
The result is - for perhaps the first time in the history of nuclear arms control talks - an American negotiating position that has been exhaustively discussed with and approved by America's NATO allies in advance.
A new high-level group coordinates planning on future deployment of the planned new nuclear missiles. The Special Consultative Group (SCG) set up at Schmidt's request examined and approved the initial American negotiating position (even though it remains a totally American decision and responsibility).
Nitze symbolized the new relationship by visiting Schmidt on his way to the Geneva opening. And the Americans will be reporting exhaustively to the SCG in the course of the negotiations.
''This is an entirely new situation,'' comments a German official with satisfaction.
Even the substantive American proposal of ''zero option'' defined by President Reagan in his Nov. 18 speech - whatever the specific evolution of the speech - is itself a position that originated in Western Europe.
No one doubts that there will be plenty of opportunity for alliance strains as the negotiations proceed and modifications and compromises become necessary. But the will, the machinery, and even the new habit of alliance consultations have been established. That is the ''quantum jump'' the Germans welcome.
At the beginning of the nuclear era the US considered details about its nuclear weapons none of its allies' business. The American nuclear umbrella protected Western Europe by a doctrine of ''massive retaliation'' - under which any local Soviet attack would be answered by American nuclear bombs on the Soviet homeland - and that was all the allies needed to know.
This situation changed with America's abandonment of nuclear retaliation - and especially with the 1967 NATO adoption of ''flexible response.'' This rather ambiguous doctrine was an attempt to compensate for NATO's conventional inferiority vis-a-vis the Warsaw Pact with a deterrent of NATO tactical nuclear weapons that were technologically superior to Soviet equivalents.
With this shift - and the increased possibility that a tactical nuclear war might be fought in Western Europe - the US began briefing its nonnuclear NATO allies more thoroughly on the capabilities and implications of its nuclear weapons deployed in Europe.
A forerunner of what is now called NATO's Nuclear Planning Group was set up, at which the US presented drafts of directives and regulations for forces in Europe equipped with nuclear arms.
Under Defense Secretaries McNamara, Laird, and Schlesinger, the scope of American briefings then gradually expanded to include regular comprehensive strategic reviews and threat assessments by the US.
When the US-Soviet strategic arms limitations talks (SALT) began in the early 1970s, there was no particular reason to inform NATO allies about the details of the talks. Superpower intercontinental weapons were at stake, not European weapons.
The Western Europeans were informed thoroughly about the resulting 1972 Salt I agreement, however, and were given increasing information about the course of Salt II negotiations from 1974 on. This was logical, since ''Eurostrategic'' weapons like the new Soviet 4,000-kilometer range Backfire bomber and the experimental US cruise missile now came into question.
In the late 1970s Schmidt became concerned that European interests were not being sufficiently taken into account in the SALT II negotiations. It not only looked as if Backfire production would not be curtailed sufficiently to preclude an additional threat to Europe, but it also seemed that the US cruise missiles would be curtailed.
Also, the Soviet threat to Europe was being sharply increased by deployment from 1977 on of the highly accurate, mobile, three-warhead, 5,000 -kilometer-range SS-20 missile, which could hit any target in Western Europe within minutes.
By the end of the decade the Soviet Union had achieved nuclear superiority in the European balance, qualitatively as well as quantitatively.
Moreover, this shift took place against the backdrop of the loss of American superiority in the strategic intercontinental balance. No less an authority than Henry Kissinger publicly questioned whether, under the condition of full superpower nuclear balance, an American president really would risk certain American devastation by responding with nuclear weapons to a Soviet attack on Europe.
In a famous speech in London in 1977, Schmidt therefore warned of approaching European vulnerability. This concern led to the 1979 NATO two-track decision to deploy new nuclear missiles in the mid-1980s - but to negotiate with the Russians about limits in the interim. It is these latter negotiations that Nitze is conducting, and that he has just reported on to the NATO foreign ministers.
Throughout the tumultuous period since the two-track decision - a period that saw the invasion of Afghanistan and the American failure to ratify SALT II - the allied exchange on nuclear issues has greatly intensified. It now amounts, in European eyes, to real consultation.