Same bed, different dreams.

This is an ancient Chinese description of any marriage of flesh, politics or ideologies. Today it is also the best way to describe the defense policies of the nations that won the Cold War. The problems created by their joint success encourage them to retreat into self-reliance and individuality.

The United States, Western Europe and Japan still live and work together in history's most successful trilateral alliance. But they look nervously into each other's eyes every morning to see what new things their partners have been imagining on their own time.

In Helsinki on Dec. 11, the leaders of the 15 member states of the European Union blessed a vision of an all-European expeditionary force of 60,000 soldiers that could carry out decisions made by the EU. These decisions would never conflict with NATO, Washington was assured, but U.S. officials do not seem totally convinced about Europe's future fidelity.

The United States has a dream: a national missile defense system that would protect American territory from being hit by ballistic rockets from rogue states. The gathering debate in Congress on this big idea adds to European fears about the United States going its own way on defense in the future, or establishing different zones of security within the alliance.

Japan's dreams of the future remain more discreet and hidden. But as it goes about building its own national reconnaissance satellites rather than depending on the United States to supply them on preferential terms, Japan appears to be inching its way toward a more assertive posture in global security matters.

The mutual apprehension that this defense dreaming is producing in allied capitals is a new factor in international relations. Always important, the psychological dimension of defense decisions being taken today for an uncertain future is overwhelming, as the U.S. Commission on National Security suggests in a recent, highly readable report entitled "New World Coming."

The United States is as far from fielding an effective territorial missile defense system as Europe is from sending combat-ready units to distant battlefields. President Clinton won't decide until June at the earliest whether to prepare for deployment of interceptors and radar by 2005. The European Rapid Reaction Force will not be ready much before then.

But the friction and at times mistrust that is growing up over this sketching of the future is already apparent--and between Americans and Europeans reciprocal--and needs to be lessened now.

France has fought for four decades to make Europe more independent of U.S. defense "hegemony." The constant sparring between Paris and Washington is nothing new, though it has produced some particularly bitter and petty reactions from both sides in recent months.

The French-American relationship today is reminiscent not so much of the Chinese adage about marriage as of an Irish story in which a battered wife is asked by a judge if she ever thought of divorce. She responds: "Divorce never. Murder frequently."

What is new and unsettling for Washington is that the drive for European defense capability within NATO is being led this time by its closest and most formidable European ally, Britain. It is British dreams that Washington is having trouble deciphering.

Being shut out of U.S. diplomacy on Kosovo in the autumn of 1998 and then having to watch NATO's air war there this year be conducted almost entirely by U.S. planes and pilots impressed Prime Minister Tony Blair with the urgent need for a serious European defense capability.

British diplomatic efforts in the weeks before the Helsinki summit to coordinate the push within the EU with Washington's thinking on NATO's future eased U.S. anxiety somewhat. Officials here had been put out of joint by Blair's earlier complicity with the French.

But at Helsinki, Germany put its weight behind the French-British initiatives with an enthusiasm and conviction that had been previously unexpressed. The drive for European defense can no longer be portrayed as just another devious French plot that will go nowhere.

European defense, like protection of U.S. territory from missiles, is rapidly moving from dream to vision to plan. The same could be said for Japan's justified ambition to secure a permanent seat on the U.N. Security Council.

Working together on these objectives need be no more difficult than was the trilateral outweighting, and outwaiting, of the Soviet Union. The manageable task at hand is to convert the new doubts into new bonds of understanding.