On this Fourth of July the fireworks burst on a great contradiction of the status of the United States in the world. How is it that we can feel so mellow about the progress that the American ideas of democracy and free enterprise have made around the globe, and at the same time be so nervous about holding our place? If we're so smart in our choice of system, why aren't we rich -- specifically, why aren't we more confident that we can stay rich enough to tackle the domestic and foreign tasks that our interests and ambitions place on the national agenda?

I ask this as one who has been struggling to put together the mental pieces brought home from two trips abroad in the past year. The first trip was to the Soviet Union, where an empire, ideology, model and threat can be seen crumbling before one's eyes. The second was to Japan, where one stands with apprehensive respect, if not awe, before a country and system that seem to have organized at least some aspects of post-industrial society notably better than we have. How should we be adjusting anxieties and resources as between the old challenge and the new?

The place to leap in is the debate over whether the United States is or is not in ''decline.'' This is a recurrent American discussion brought to a fresh boil about two years ago by Paul Kennedy's suggestion in ''The Rise and Fall of the Great Powers'' that the American global position was coming into the parlous condition of ''imperial overstretch'' that had undone great powers in times past. He caught the mood of strategic anxiety that existed before Mikhail Gorbachev's foreign policy ideas had sunk in either in Moscow or in Washington; it made his book a bestseller.

Many people, especially those conservatives who were put off by the very notion of decline, later felt that no sooner had the Kennedy book seen the light of day than it was run over by a truck in the form of the Soviet Union's East European collapse and its deepening internal deterioration. The parallel global blooming of democracy and free enterprise produced the comforting conclusion in these quarters that Yale's Kennedy had spotted the wrong falling star.

In fact, he didn't, and he is miscast as a ''doomsayer.'' But of course when historians let themselves get predictive they are no less immune to surprises than politicians and journalists, and no more than the rest of us did Kennedy anticipate the extent of Kremlin convulsion and policy review. These developments are what suddenly made the match of American resources to American overseas commitments no longer a daunting problem. The felt requirement to prepare indefinitely for heavy political/military challenges abroad has been shrinking before our eyes, most conspicuously in Europe -- though the change is being reflected only slowly in the Pentagon budget.

The change makes something of a prophet of another policy-minded scholar, Harvard's Joseph Nye. His study of the changing international scene, entitled ''Bound to Lead,'' nicely survived the revolution in Eastern Europe that happened to take place between its writing and its actual publication in the spring. The mood he catches is one of strategic relief and economic concern. The indexes he favors in calculating America's place in the economic and political firmament leave the United States well within the comfort range, though he issues bracing calls for Americans to keep up with the Japanese and otherwise to find a cooperative place in a troublesome world.

Will we do it? The Fourth of July is traditionally a time for renewing dedication to national purposes. Politically, in deliberations on budget priorities and in matters of education, savings, investment, technology and trade, we are still washing back and forth in the policy sea. There are tendencies in our political debate but no final decisions.

We have not entirely let go -- nor should we quite yet -- of our long and fearful fascination with the Soviet Union, though it has to be said that in public attitudes and policy architecture we are keeping up pretty well. Nor have we fastened on to a new concentration on the more diffuse domestic difficulties posed and represented by Japan; here it seems to me we are definitely lagging behind the needs of the times.

Caution, sometimes reflecting prudence, sometimes masking indecision, is the American style of the 1990s: a national leaning, not just a Bush administration preference. It is better suited to help us on the Soviet side than the Japanese side. There our affluence, or perhaps more precisely our credit rating, is allowing us to juggle hard choices a bit longer. But surely not indefinitely.