A DISTURBING shift has occurred in American politics: Our leaders no longer talk much about the future, at least not with any real optimism. In an atmosphere of fiscal paralysis and frequent scandal, political leaders have become crisis managers, too consumed with the present to think very far ahead. They have also grown more cautious and technocratic, less willing to argue passionately about the future of the nation. These trends help account for the public's declining interest in politics. But for my generation especially - those of us now coming of age and destined to live most of our lives in the 21st century - a political discourse which does not look to the future is of little interest. Worse, it is a discourse devoid of hope. With a presidential election less than a year away, and with the perception growing that the country is stagnating, an opportunity is at hand to reinvent a politics of the future. A central theme of this politics should be national investment. The idea is not unfamiliar. For much of the 20th century, investing in tomorrow was an ongoing American crusade. Major initiatives in areas like education, housing, and infrastructure created a hopeful framework for discussing the future. Such optimism and ambition no longer infuses American politics. Two decades of sluggish economic growth are partly to blame. More recently, the federal budget deficits, worrisomely high since the early 1980s, have served to limit the imagination. But most significantly, a decade of rule by anti-government presidents ended White House efforts to choreograph national progress. The free market, Americans were told, would be the locomotive which would pull us to a better future. During the 1980s, investment was a word that Republicans used when talking about personal finances, not public policy. Between 1980 and 1990, federal nondefense spending declined as a percentage of the gross national product. In the process, government investment in the future plummeted, with cutbacks made in such programs as job training, preschool education, and research on renewable energy. In pivotal areas which will affect national performance in the 21st century, the United States is woefully deficient: one in four children under the age of six live in poverty; 25 percent of high school students do not graduate; America lags behind other industrial nations in the training of scientists and engineers. Today, members of both Congress and the executive branch are so overwhelmed by the current crisis that it is no wonder they don't speak much about the future. This year's budget deficit will run as high as $350 billion, adding to a national debt which is already over $3 trillion. The costs of the savings and loan scandal are just now being felt, and are likely to grow more burdensome in the next few years. RECLAIMING a prosperous future will entail considerable pain. In the short term, taxes must be raised; over the long run, private consumption will have to be curbed. Sacrifice of this scope is not beyond the American people. The US is the most lightly taxed industrial nation in the world, and polls consistently show that most Americans would support higher taxes if they were confident the money would be well-spent. But to sell such sacrifice national leaders must put forth a compelling vision of the futu re. Investment is an idea at once easily understood and eminently sound. A politics of the future which centered on refurbishing the crumbling foundations of American society could build a consensus for higher taxes, especially if investment initiatives were designed to benefit all. Infrastructure and education are two good places to start. Over the last four decades, investment in infrastructure has declined, falling from nearly 7 percent of federal nondefense expenditures in the decade after World War II to around 1.2 percent in the 1980s. The consequences of this neglect are everywhere - from midafternoon traffic jams to unsafe bridges to airport congestion. Investment in this area would benefit both the average taxpayer and future generations. The same holds for education. Republican claims to the contrary, more money is needed for education - a lot more. As writer Jonathan Kozol has documented in disturbing detail, many US schools are barely able to function because of inadequate facilities and supplies. More federal money is often the only remedy to this situation, given the fiscal woes of city and state governments. Successful new investment in infrastructure and education could help revalidate an axiom of national life seemingly forgotten in the last decade: taxes are worth paying, government can make a difference, and the needs of the future should come before the impulses of the present. A focus on long-term goals would also make politics more meaningful. Surely Americans care more about the bread-and-butter issues that govern their lives than they do about scandals and political fights which generate sensational headlines but don't affect them personally. A final benefit of renewing a politics of the future would be to engage younger Americans, who participate in politics less than any other age group. Social scientists can debate the precise reasons for this apathy, but cynicism about political leaders is surely one of them. By failing to articulate a vision of the future, the generation which now wields power offers little to younger Americans like myself.