IN 1941, AMERICANS set out to destroy a totalitarian German empire that already dominated Europe and planned to dominate the world. By 1949, we were well on the way to rebuilding -- and were already virtually allied with -- a parliamentary Federal Republic of Germany that saw its salvation not in resisting, but in cooperating with its occupiers.

Postwar historians have produced two distinct and largely contrary explanations for this turnaround. The orthodox view is that the United States was reacting to the threat of Soviet expansion in Europe by rebuilding western Germany. Revisionists have argued the opposite -- that the Russians were responding to the American nuclear monopoly, and to U.S. economic initiatives seen as a threat to the Soviet sphere of influence in Eastern Europe.

In fact, neither view is a very reliable guide to what really happened. Both neglect such crucial and complicated (if undramatic) factors as France's need for security from Germany, Europe's need for German coal and a Republican U.S. Congress' determination to limit the costs of the American presence in Europe.

The remarkable story of Germany's defeat and postwar transformation begins with America's decision to fight Hitler. Embittered that World War I had not "made the world safe for democracy," as President Woodrow Wilson had hoped, Americans were initially reluctant to get involved at all.

The collapse of France in 1940 showed what a dangerous game that was. But even then, it took the Japanese raid on Pearl Harbor more than a year later to bring the United States into the war on the side of Britain and the Soviet Union.

Roosevelt's declaration in January 1943 that Germany would have to surrender unconditionally basically completed America's agenda of war goals. Henceforth, Germany's future would be determined by American, Soviet and British interests and negotiations between them.

Diplomats and civil servants were left to settle such seeming technicalities as whether Germany was to be dismembered or partitioned, liberated or occupied, dismantled or reconstructed.

Should Germany remain intact? The allied answer was a qualified yes. In December 1943, at their famous summit meeting in Tehran, Roosevelt, Churchill and Stalin all fantasized out loud, and at length, about dismembering Germany. Roosevelt, for example, proposed five little postwar Germanies to replace the existing one, with international administration for the ports of Hamburg, Bremen and Luebeck.

But enthusiasm for radical dismemberment cooled as allied thoughts turned progressively from the war against Germany to postwar relations with one another.

By the last of the great wartime summits (Potsdam in the summer of 1945) it had all but vanished from the table. Germany lost a third of its pre-war territory to Poland and the Soviet Union; but Germany was still regarded as an economic unit.

A second issue facing the victors was whether a defeated Germany should have a central government. By the end of the war, America, Britain, and the Soviet Union had invited France to share in a collective administration of the country through a "control commission" in Berlin in which all decisions were to be unanimous. Each power would otherwise be responsible for its own zone of occupation. The American zone was in the scenic but underdeveloped German south. Britain occupied the industrial northwest, and France a zone in between. Berlin, the capital, was also divided into four occupation zones. But the Germans themselves would have to bear the costs and assume the responsibility for day-to-day administration.

For different reasons, Britain, the Soviet Union and parts of the U.S. government favored retaining the industrial capacity of a defeated Germany. The British knew German coal and steel were essential to European recovery. The Russians were desperate for reparations and keen for access to the Ruhr, Germany's coal and steel region. And U.S. Secretary of State Cordell Hull and Secretary of War Henry Stimson, recalling the disasters of the 1920s and 1930s after German industrial capacity was diverted and disrupted by the World War I peace settlement, also favored rebuilding German industry.

They were resisted by Treasury Secretary Henry Morgenthau, who insisted there would be no peace in Europe until Germany was "pastoralized." For a few weeks in September 1944, he almost persuaded Roosevelt to make his plan official U.S. policy.

Roosevelt died before it was clear where he stood. His successor, Harry Truman, had no other plans for Germany other than carrying out what he thought were Roosevelt's intentions. But he did believe the State Department should be in charge of foreign policy. Treasury's hardliners nonetheless won a partial victory.

At the 1945 Potsdam meeting, the allies took what was basically a State Department position. Germany would remain a single economic unit, not least because Americans wanted a German economy that could produce reparations without American subsidies. In return for industrial reparations, the Russians agreed to deliver agricultural commodities from their own predominantly agricultural zone of occupation. The allies also agreed to German disarmament, demilitarization, denazification amd democratization, though definition of terms was left notably vague.

But within the American-occupied zone, where U.S. bureaucracies bargained only with each other, Treasury got its way. Joint Chiefs of Staff directive number 1067, the policy guideline for the American zone which reflected the positions of Treasury and the War Departments, forbade any social contacts between Americans and Germans; authorized the dismantling and seizure of Germany industries; and allowed relief to the devastated German population only as needed to prevent outright starvation or epidemic disease.

The 1945 Potsdam accords between the four occupying powers, together with JCS-1067, reflected the demands of many constituencies at home and abroad.

What the post-war agreements ignored were the realities of the German scene. There was no way for Americans to transfer German war reparations to the Russians and still enjoy a cost-free occupation; no way for Americans to be tough alone, while less-tough policies were being followed in the British and French zones; no way to starve and punish Germans and still make them work; no way to feed 12 million refugees from eastern Germany without the farms in Polish hands or now subject to Soviet land reform; no way to satisfy British and American diplomats who wanted a federal Germany, Russians who were still flirting with a united communist Germany, and the French who lusted for the coal-rich Ruhr but would otherwise have been as happy with no German state at all.

By 1947, the Potsdam agreements were in bad trouble, JCS-1067 was defunct, inter-allied rapport was close to breakdown and Congress had all but declared the occupation a failure.

Yet within a decade after that, a Germany existed in the former western occupation zones that Swiss journalist Fritz Rene Allemann could accurately describe as "a well-ordered and above all unambiguous society, not without tension but solid, rather more conservative than innovative, perhaps a bit boring but remarkably normal."

Both prevailing explanations of this turnabout are right in pointing to the Russians and their motives as a mainspring of U.S. policy. But the orthodox ("Soviet threat") version obscures the underlying confusion and caution of the Soviets, while the revisionist ("American threat") version overlooks the amazing capacity of Soviet policymakers to lose friends and influence people to do things that only confirm their fears.

Determined to "democratize" their zone in their own ideological fashion, the Russians declared an instant social revolution, confiscating businesses, redistributing and collectivizing land and generally taking over. Meanwhile they carried off whatever their reparations officers could get their hands on.

Even though the Soviet zone actually led the western occupation zones in industrial reconstruction, agricultural policy was a disaster and produced a a stream of hungry refugees whose stories scared Germans in other occupied areas. Moreover, the Soviets did not make good on their pledge to ship farm commodities west, which western authorities took as a deliberate obstruction of the agreement to treat Germany as a single economic unit.

Even had the Russians wanted to comply, which is possible, there was no food surplus with which they could. When the Soviets failed to make good on their pledge to supply farm commodities, the Americans suspended reparations shipments.

The allied impression of Soviet policy was at least half right. The Soviet zone was, in fact, receding from collective control. The Russians had no interest in Western-style democracy, especially after local communists took a beating in 1946 in the only free election held in the Soviet zone of occupation.

At about the same time, American and British policy makers had begun to recognize the cost of JCS-1067, and of unilateral French and Soviet seizure of war reparations. To the British, German economic collapse meant paying from their own frayed pockets for millions of people they had just defeated. America would then have to bail out Britain.

A second problem associated with Germany's economic problems was that they made European recovery heavily dependent on supplies from the United States. But these could only be bought for dollars, which few Europeans either had or had any hope of getting.

A third problem was that hunger and unemployment in the western zones of Germany threatened to make the Soviet zone will all its failings look good by comparison.

And so, after a series of abortive post-war summits, the British and American governments decided in April 1947 to merge their zones in the name of economic efficiency. The Russians, and the French for the moment, carried on alone. A few weeks later, in a graduation speech at Harvard, Secretary of State George C. Marshall proposed what was to become the Marshall Plan, history's biggest economic-aid plan.

Within months, Soviet reaction to western decisions to reconstruct the western zones of Germany had led to the blockade of road, rail and water routes leading from the western zones to Berlin. The western allies neither challenged the blockade nor retreated. Instead, for the first time ever, they fed and supplied several million people entirely from the air. West Berliners stood with them, neither running away nor begging for rations from East Berlin. Before the blockade, Americans called Germans "them." Afterward West Berliners, at least, were "we."

But the reconstruction of Germany only worked out as it did because three crucially interested parties adjusted to new circumstances.

One was the French, who originally rejected any German recovery at all. Another was the Germans themselves, whose consent if not advice was obviously essential. The last was American opinion, including a Republican Congress that was elected in 1946 to cut public spending spending by 40 percent, but would now have to foot bills it never imagined for German, and European, recovery.

Each deserves more attention, and even appreciation, than Americans have usually given. That things turned out incomparably better than they did after World War I is a testimonial to one of those brief and exhilarating moments when people understand that things have changed and actually act on what they learned.

For the French, this moment of truth was the realization that the only way to the promised land of German resources, American aid and the modern industrial infrastructure that had eluded them since the mid-19th century, was economic partnership with the Germans.

For the Germans there were two moments of truth. One was the realization that the new oppression of East Germans could lead to rehabilitation, even liberation of West Germans. The other was the discovery that only international cooperation promised Germans any recovery of national independence.

In accepting the first truth, West Germans, who were not born to democracy, nonetheless achieved it after having it thrust upon them. By accepting the second, a people that had only recently set records for nationalist fanaticism suddenly became enthusiastic Europeans.

For Americans, the moment of truth led to a foreign policy that was neither dovish nor hawkish, utopian nor isolationist, but was nonetheless courageous, generous and shrewd.

Fear of the Russians really was a motive of U.S. policy. But senior policy-makers were at least as interested, and as anxious, about European recovery as an end in itself, and Congress was at least as interested in cutting costs and European commitments as it was in containing the Russians.

The revisionists also have a point in saying that it was American initiatives that reshaped the postwar world. But it is hard to say that these initiatives were born of superior military muscle or lust for markets. By 1948, an American Army of over eight million had declined to less than one million, the Air Force included. Faced with a test like the Berlin blockade, America's nuclear monopoly turned out to be nearly irrelevant. At the same time, foreign trade, let alone investment, was only a tiny part of a prodigious boom at home.

Neither President Truman nor Gen. Lucius Clay, the American military governor in 1948, saw grounds for anything but caution on Berlin. What turned American policy from defensiveness to confidence was a rather different set of arguments from those usually mentioned.

Stable democratic government in Western Europe required European recovery. European recovery would contain the Russians, according to U.S. planners. German reconstruction was necessary to European recovery. French consent was necessary to German reconstruction. Dollar aid and recognition of French security needs were necessary to French consent to American initiatives in Germany. Congress wanted European recovery, not prolonged dependence.

In a time when U.S. foreign policy often seems muddled and simplistic, it is worth recalling the premises of the early postwar U.S. planners: that American goals, not Soviet initiatives, should define the agenda of American foreign policy; that American democracy can be powerfully attractive abroad; that economic strength can matter more than military power; that we have more to gain than fear from the independence of our allies; that allies and Congress can be trusted without damage to public policy and the national interest.

Humble and temporal truths, they led us back from the dead end that wartime planning had led us into, and from there to the world we still call "post-war" after 40 years.