The movable feast shifted from sunny Madrid to wintry Stockholm this week as 35 European nations (well, 33 European, plus the United States and Canada) began their latest marathon meeting.
The Stockholm conference, son of the Madrid conference, son of the Belgrade conference, son of the Helsinki conference, opened with restrained Nordic pomp Jan. 17. It will run several years, if it is anything like its predecessors.
But its most important role this week is to provide a forum for the big powers. Already the Americans and Soviets have used it to stress their own arms proposals, both sides calling for different versions of a ban on chemical weapons.
And the big attraction that has drawn 1,300 reporters here is the first tete-a-tete, due today, between American Secretary of State George Shultz and Soviet Foreign Minister Andrei Gromyko since their confrontation after Soviet fighter planes shot down Korean Air Lines Flight 7 last September.
Once that meeting has passed and the 35 foreign ministers have all had their moment of glory, the real work of the conference on confidence- and security-building measures and disarmament in Europe will begin next week.
Actually, no disarmament will be discussed at the first phase of the conference due to end in 1986. The mandate from Madrid setting up this conference stipulates that the initial stage will deal only with ''confidence-building measures'' - that is, steps like mutual NATO/Warsaw Pact notification of large military maneuvers. The aim is to help prevent surprise attack.
In the run-up to the Stockholm conference, the Warsaw Pact also re-proposed a Europewide ban on chemical weapons. And Mr. Shultz, in his address to the conference Tuesday, promptly announced that US negotiators would in coming months present in Geneva ''a draft treaty for the complete and verifiable elimination of chemical weapons on a global basis.''
But these are matters not for the Stockholm conference but for the UN Committee on Disarmament. Human rights, too, which were such an important part of the Helsinki Final Act of 1975 and of the Belgrade and Madrid reviews of that original Helsinki Conference on Security and Cooperation in Europe, are excluded from the agenda this time around.
In his speech Tuesday Mr. Shultz did assert that human rights are ''central to any discussion of European security.'' But the emphasis of his very general preview of the Western position was on confidence-building measures, including an optimistic call for ''annual previews of military exercises.''
When France proposed a conference on disarmament in Europe back in 1978, the idea was that real disarmament would be the eventual goal in a geographic area including all of Europe as far east as the Urals. This would represent an enlargement from the territory of the conventional forces reduction talks in Vienna (the two German states plus the Benelux countries, Poland, and Czechoslovakia).
This is still the ultimate goal, but the focus well into next year is going to be restricted to ''military transparency,'' as the new Western buzzword has it.
The Stockholm conference's confidence-building measures (or CBMs, as they are already known) won't address the most urgent problem in East-West military confrontation. They won't reinstate the Euromissile and strategic nuclear arms control talks the Soviet Union suspended late last year after NATO began its new Euromissile deployments in response to the six-year Soviet buildup of SS-20s.
CBMs are not negligible, however. They address a very real concern: NATO's fear of a surprise attack by the conventionally superior Warsaw Pact in Europe. NATO observation of Warsaw Pact military exercises could help verify, for example, that such maneuvers were not being used to disguise massing of an attack force.
To this end the joint Western proposal at Stockholm is expected to call for extension of and ''politically binding'' compliance with the CBMs agreed on at the original Helsinki conference. Those 1975 CBMs included three-week advance notification of military maneuvers involving more than 25,000 troops, along with optional invitations to observers of the other side to witness the maneuvers. The territory covered included a strip 150 miles wide on the western border of the Soviet Union.
The Helsinki measures did not, however, apply as far east as the Urals. The Stockholm conference covers ''the whole of Europe as well as the adjoining sea area and air space'' - a span that is understood to include the European Soviet Union to the Urals as well as some American naval and air power in the Mediterranean and Atlantic.
Western officials say the Soviets have not notified the West of all exercises involving more than 25,000 troops or not invited Western observers to witness any exercises since Soviet troops invaded Afghanistan in 1979.
Nonetheless, there is some indication of more Soviet interest in advance notification and even observation of military maneuvers. Last June a spokesman at the conventional forces reduction talks in Vienna announced that the Warsaw Pact nations had made new proposals that included ''on-site verification.'' He did not elaborate. It is not clear how far the Soviet bloc was or is prepared to accept the Western proposal for on-site inspection that has been on the table since 1979.
But former Deputy Assistant Defense Secretary James Blaker says the Soviets may be getting worried about the possibility of some preemptive NATO attack under the new US concept of ''air/land battle'' and ''deep strike.'' If so, the Soviet Union, too, may have an incentive to use observers to verify that the adversary alliance is not using maneuvers to launch an attack.
If so, the Stockholm conference could make a modest ''new departure,'' despite the current low point in East-West relations.