LONDON, Jan 25, 2001 -- (Reuters) Worried European allies are groping for a response to new U.S. President George W. Bush's determination to give priority to developing a shield against ballistic missiles.

The drive for National Missile Defense (NMD), symbolized by the choice as defense secretary of Donald Rumsfeld, author of an influential report on the missile threat from "rogue states", is potentially the most divisive issue in NATO for years.

No European government publicly supports the plan, on which former President Bill Clinton left a final decision to his Republican successor. France and Germany warned last year it could trigger a new arms race.

But after months in denial, policymakers in London, Paris, Berlin and Brussels are resigned to the near certainty that Washington will go ahead with some form of missile defense, although they are far from agreeing on how and when to respond.

"Many Europeans question the seriousness of the threat, worry about the cost, doubt whether the technology can ever be made to work, and have deep reservations about the international implications, particularly for arms control and relations with Russia and China," said Philip Gordon, a former director for Europe at the White House National Security Council.

Russia and China are vehemently opposed to NMD, which they see as a threat to their own nuclear forces, even though U.S. officials insist it is intended to deal only with small numbers of potentially nuclear-armed missiles from states such as North Korea, Iran or Iraq.

DIFFERENT EUROPEAN INTERESTS

Bush and his aides have spoken of a system that would protect not only the United States but key allies as well, while Clinton foresaw a more limited, land-based defense against missiles fired in error or by "rogue" enemies.

In a comment at his Senate confirmation hearing that worried some Europeans, Rumsfeld called a 1972 treaty with Moscow barring such systems "ancient history".

The European allies do not have identical interests on NMD, but they share a desire to build stable relations with Russia, preserve the framework of arms control and avoid an arms race.

All can agree to encourage Bush to negotiate any changes to the 1972 Anti-Ballistic Missile treaty with Moscow rather than tear it up, as his more hawkish supporters advocate.

French analyst Camille Grand has quipped that NMD could otherwise stand for "no more disarmament".

Western Europe's two nuclear powers, Britain and France, have particular concerns about NMD's implications for their own small nuclear forces and for the logic of deterrence.

They have held discreet consultations on NMD but they differ on the extent of the threat and on the appropriate forum in which to debate the issue, diplomatic sources say.

French Foreign Minister Hubert Vedrine has said it is "not very serious" to believe that states like North Korea, Iran, Iraq or Libya could threaten the world's sole superpower, calling such threats "microscopic -- or theoretical".

Britain and Denmark are in the most sensitive position because they expect U.S. requests to upgrade early warning radar stations on their territory at Fylingdales, England, and Thule, Greenland, for NMD. Both countries have center-left governments with an anti-nuclear history and fear public protests.

Their foreign ministers agreed last week not to take a position on U.S. plans until Washington made a formal request.

"We have not been asked any question and we will give an answer when the Americans have decided they are ready to ask that question," British Foreign Secretary Robin Cook said after talks in London with his Danish counterpart Mogens Lykketoft.

OPPOSITIONS PRESSING

Britain's Conservative opposition has tried to exploit the government's discomfort by endorsing missile defense and urging Prime Minister Tony Blair to cooperate with Bush.

Aides say Blair is keen to avoid a debate about NMD before a general election he is expected to call in May.

Sir Michael Quinlan, a former top defense official and nuclear deterrence theorist, said British doubts about NMD had been "communicated so discreetly or so gently that the (U.S.) administration could portray Britain as an already-persuaded supporter of the project".

Germany's conservative opposition is challenging the deep reservations about missile defense articulated by Chancellor Gerhard Schroeder and Foreign Minister Joschka Fischer.

Christian Democratic (CDU) foreign policy spokesman Volker Ruehe, a former defense minister, called for Europe to "actively seize" the chance to participate in the U.S. project.

Klaus Becker, a senior fellow at the International Institute for Strategic Studies, said missile defense was not high on the European political agenda and governments might as a result miss a chance to sway the Bush administration early on.

"The Europeans won't come to a clear formulation of a joint position in the first half of this year, although that would be the best way to influence the U.S. policy review and feed in some European concerns," Becker said. "As far as I know, they are not even trying."

He said European interests included keeping Russia on board, pursuing joint approaches to stopping the spread of nuclear and missile technology, persuading Moscow to replace its aging nuclear-tipped anti-ballistic missiles and including shorter-range nuclear missiles in arms control negotiations.

The Europeans might also want to link cooperation with NMD to U.S. support for the European Union's planned Rapid Reaction Force, a greater opening of the U.S. defense market and sharing of intelligence and technology with the allies.

The experience of the Reagan administration's "Star Wars" anti-missile program in the 1980s was that the European allies first criticized the plan, then scrambled for research contracts and a share of the technology.