LONDON, JULY 5 -- Behind the bargaining at the NATO summit this week lies a major power shift that has taken place in the 16-nation alliance over the past year. West Germany is up and calling many of the shots, Britain and France are down and grumbling, and the United States is in the middle, trying to keep everyone happy.

On the sidelines is an unlikely but important kibbitzer: NATO's former adversary, the Soviet Union.

The new tilt toward Bonn was evident as Western nations accepted, despite misgivings in some cases, West Germany's position in their opening summit statements today on the future of the North Atlantic Treaty Organization.

President Bush won broad support for a series of initiatives explicitly proposed in deference to the special political and military needs of a unified Germany, and to Western desires to win Soviet approval for Germany's continued membership in NATO, officials here said.

It was a pairing of the interests of a new superpower, Germany, with an old one, the United States, that shaped the new NATO consensus.

Only Britain's Prime Minister Margaret Thatcher has publicly resisted the joint call of Bonn and Washington to move the alliance gently but more decisively away from its Cold War military strategy.

The contrast between the new Germany and the older leaders of Europe was probably most evident in West German Chancellor Helmut Kohl's suggestion that NATO be transformed "with far-sightedness and creativity," including "adapting our military structure to the new situation on a large scale."

In sharply different remarks, Thatcher pointedly invoked memories of the postwar years of 1919 and 1945 and warned her fellow leaders that "the wise man guards against the future as if it were the present." She added the alliance should keep up its current defenses because "you never know where the next threat will come from."

In the middle of this philosophical gap, was the Bush administration. U.S. officials made no secret of their fundamental goal for the summit: to help Bonn persuade Moscow that Germany should remain in NATO.

Bush decided the best means of doing so would be to provide Moscow with assurances German territory will no longer serve as the front line of the Cold War, a role German officials had already said they are unwilling to retain in the aftermath of the Warsaw Pact's disintegration.

At least two German-inspired, Bush-backed ideas appeared to win general support. One was the U.S. proposal to eventually withdraw all American nuclear-tipped artillery shells, which Bonn now views as a military threat to its own people in the East. Another was Bush's call for permanent staff and regular meetings of the Conference on Security and Cooperation in Europe, a loose-knit group that Moscow and Bonn have both promoted as a "pillar" of Europe's new security arrangement.

These suggestions were accepted, amid some grumbling, by London and Paris, which privately share some of Moscow's anxieties about German unification but favor holding fast to existing doctrines and weapons instead of making new concessions to the East.

Thatcher's flashpoint today was a proposal by Bush to make clear that NATO would use nuclear weapons only as "a last resort" in response to any Soviet aggression in Europe.

While some Western officials contend the initiative is a largely cosmetic policy shift, Thatcher expressed concern that the promise to delay nuclear detonations as long as possible during an attack by conventional forces unnecessarily ties NATO's hands. She warned that the overall strategy of a "flexible response" to the Soviets might become unduly "inflexible" and impair the deterrence of war.

Kohl, meanwhile, expressed contrary concerns. He made no mention at all of "flexible response" or of a continued need for nuclear weapons in Germany and spoke approvingly of "further drastic cuts" in U.S. short-range nuclear-tipped missiles deployed on German soil.

A spokesman for Bonn Foreign Minister Hans-Dietrich Genscher said in response to questions that his government had no complaints to direct toward Washington. "We support the whole Bush {draft} declaration," he said in a clear expression of how closely the two nation's interests appear to have been joined.

Tonight, the British agreed to accept the U.S.- and German-backed formula for using tactical nuclear weapons as "a last resort" after other language was added to alleviate some of Thatcher's concerns, a British official said.

Washington's willingness to pursue a common agenda with Bonn was also evident in a decision, revealed late today by a senior U.S. official, to agree that German troops could be limited in an East-West treaty on conventional forces later this year.

The Bush administration had earlier joined France in opposing such prompt limitations, but now says it will accept the idea if Bonn wants it, the official said on condition that he not be identified.