WASHINGTON — "You could say that we've won," a senior U.S. official remarked.

"Our policy of 'differentiation' in Eastern Europe--of treating each nation differently depending on how they behaved--has succeeded. Or at least, it's been (overtaken by events). In either case, now we need a new construct, a new concept that embraces the region as a whole."

Indeed, the remarkable changes that brought down the six regimes of the East Bloc in 1989 have also created a compelling need for a new U.S. foreign policy.

But only in coming weeks and months will the quest get the attention it deserves from the broader bureaucracy, according to officials.

"Nobody wants to tear up his old policies before he has to," explained one official, "and there is governmental inertia to overcome. And so far, the President has not been hot for a new policy."

Without a broad new approach soon, officials see several possible problems:

-- That each U.S. agency, the Congress and private U.S. companies will go their own way on such issues as economic aid to individual East European nations. This could create inconsistent and confusing precedents that could be contrary to whatever U.S. policy eventually emerges.

-- That West European allies will move smartly in directions or at a pace contrary to American interests. West German efforts toward reunification with East Germany provide a good example of such risks.

-- That the flurry of democratic elections in the Eastern Europe in coming months, beginning in March in Hungary, will require a more coherent and fine-tuned U.S. strategy toward the kinds of parties and leaders it would like to see win there and toward the new governments when they emerge.

Certainly President Bush will want to have a more concrete policy than at present when Soviet President Mikhail S. Gorbachev comes to the Washington summit in June.

"The keys to the future of Eastern Europe," said one U.S. analyst, "are the United States, Western Europe and Japan. Gorbachev provides an active permissive function by not intervening, but the West must supply the wherewithal in money, short- and long-term. And the United States will be the most influential single player even though we are a bit strapped (for funds) just now."

A multitude of issues face U.S. policy-makers. They include how to help Eastern Europe integrate economically into Western Europe and how to control a reunified Germany that might seek to fill part of the power vacuum being left by the Soviets.