THE UNCERTAIN FUTURE of the Democratic party and the broader question--whither liberalism? --have been brought into sharp focus in the past several months, especially since the sweeping election of Ronald Reagan and the Democrats' stunning loss of control of the Senate for the first time in a quarter century. The handful of new faces associated by the media with fresh ideas about their party and ideology--including the likes of Senators Paul Tsongas (D-Mass.), Dale Bumpers (D-Ark.), Gary Hart (D-Col.) and John Glenn (D-Ohio)-- have appeared regularly on Meet the Press-type talk shows and have been quoted in The Washington Post and The Wall Street Journal as possible leaders (read, presidential candidates) of the future.

Of these and other purveyors of "new ideas" cited by the Great Mentioner, Paul Tsongas is distinctive. He's the only one so far to put his personal blueprint for liberalism and the Democratic Party into a book, called The Road From Here: Liberalism and Realities in the 1980s.

Who is Paul Tsongas and how did he get to be a "leader of the future" and the author of a well-promoted book? Tsongas is a 40-year-old Massachusetts Democrat who first came to Washington in the Watergate year of 1974, beating a Republican incumbent to win election to the House of Representatives; four years later, he defeated scandal-plagued Senator Edward Brooke and became the junior senator from Massachusetts. In four years in the House and his first two in the Senate, Tsongas earned a reputation as an attractive, diligent young liberal legislator, but he labored along with the mass of his colleagues in relative obscurity. Then, in June 1980, Tsongas became the focus of national attention.

At the height of the 1980 election campaign, with the contest for the Democratic presidential nomination between President Jimmy Carter and the senior senator from Massachusetts, Edward M. Kennedy, becoming incresingly bitter, Paul Tsongas gave the keynote address to the national convention of the liberal Americans for Democratic Action (ADA). He called for a fundamental reassessment of traditional liberalism. The liberal mentality, he said, could no longer live off the legacy of the New Deal--it had to confront new realities, from the energy crisis to the Soviet threat to the economic crunch. New thinking was needed for a new era.

Such a speech might not seem like anything terribly extraordinary--except that it was delivered during the presidential campaign by Ted Kennedy's Massachusetts sidekick in the Senate. In this context, it could be taken --and indeed was--as a repudiation of Kennedy's ideas, rhetoric and themes. When a David Broder column on the Tsongas speech appeared the next week, the Boston Globe titled it, "End of Kennedy-Style Liberalism?"

A classic man-bites-dog twist thus catapulted Tsongas onto the national stage. As he admits in The Road From Here, the sudden attention (and hostility from the Kennedy camp) caused Tsongas some discomfort, but not enough to dampen his new-found celebrity (indeed, he encouraged it further with his own New York Times op- ed column paraphrasing the speech the following week.)

From there, and with encouragement from his colleagues and others, Tsongas moved to write a book expanding on his ideas and fleshing out his ADA speech. For several months earlier this year, the Tsongas book project was a favorite subject for gossip in Senate corridors and cloakrooms. Some said with surprise that he seemed actually to be drafting the manuscript himself (an unusual practice for a senator). Others wondered why he was taking such a risk; if Tsongas really offered new ideas, he would be seen as utopian or kooky, while a simple restatement of common themes would be viewed as banal. A book classified as either unrealistic or trite would damage the bright Tsongas image and thus set back his political career.

The Road From Here is neither kooky nor banal. While it is uneven, it shows intelligence and an impressive command of a wide array of policy topics. It is written with an open and intelligible style. But it demonstrates that, for liberals and Democrats, the road from here will be long and winding, with no central map to guide and no bright vision of what we'll find at the end of the road.

The overall theme of Tsongas' book is that liberals must blend their ingrained compassion for the weak and disadvantaged with a hard, undogmatic look at today's problems and limitations. "The message of this book," he notes, "is the blending of realism and compassion in a manner that does not disrupt society." Reality is the watchword. It pervades the book, which is organized around eight substantive chapters, from energy to inflation, subtitled in order from "The First Reality" to "The Eighth Reality."

Each of these self-contained chapters includes a concise description of current needs, policy alternatives, economic and social tradeoffs, and suggestions. Mixed in is an array of examples from Massachusetts and Tsongas' own political experiences, including a term as a Peace Corps volunteer in Ethiopia and local political office in Lowell. Each chapter is well written, thorough and logical. Some are excellent. The chapter on "War and Peace and the Soviets--The Second Reality" is an aggressive defense of a human rights-oriented foreign policy from the perspective of countering a real and massive Soviet threat. There is no mushy moralism here, simply the best defense I have seen, on the conservatives' own turf, of a Carter-type foreign policy. Similarly, "International Trade--The Sixth Reality," is an insightful articulation of ideas largely ignored in broader political discourse, and bolsterd by Tsongas' service on various international trade panels in Congress.

Tsongas occasionally gets sidetracked in minutiae (as in a lengthy discussion of renewable energy resources, or a call for repeal of the Glass-Stengall Act--say what?), but usually he discusses the broader impact of issues and alternatives with just the right amount of detail. Each chapter would probably impress Jimmy Carter with its logic and grasp of the subject.

But the central problem of this book, like the central problem of Jimmy Carter's presidency, is lack of theme --after we're through the fine print of logical and realistic policies, we're left with the feeling, in Dorothy Parker's phrase, that there is no there there. Tsongas offers support for the free marketplace combined with a defense of a governmental role overseeing it; a call for a strong foreign policy to counter the Russians combined with a demand for a vigorous human rights and Third World-oriented stance; a clarion for environmental protection combined with a plea for careful expansion of nuclear power.

All these positions add up to a set of discrete values and avenues for getting through, with some foresight and long-term planning, the big problems of the 1980s. They do not hang together in an overall framework encompassing the role of government and of the individual in society, bringing in broader concepts like equality, liberty, rights or freedoms. There is just too much pragmatism. In contrast, whether one likes it or not, it is clear that Ronald Reagan has a philosophy; his framework is an important part of Reagan's immense appeal to the American people, including many who don't agree with it. The apparent lack of an underlying philosophy was in turn an important part of Jimmy Carter's inability to capture the American imagination or enthusiasm. If Tsongas' book is any guide, the Democrats have not progressed in this area. They have post-New Deal policy options, but no post-New Deal philosophy.

Just as importantly, the tone of Tsongas' book is downbeat. The emphasis is on hard choices for difficult times ahead. "We must plunge into the icy waters," he says. This is, undoubtedly, realistic. But compare a plunge into icy waters with Reagan's "if we follow my policies, happiness and prosperity lie ahead." Which sounds more attractive? In the 1930s, it was the Democrats who captured the positive side, optimistically and enthusiastically expressing Jeffersonian ideals and goals, in contrast to the dour, doomsday Republicans. Now it is the Democrats' turn to be downcast and pessimistic. If there is a future for the Democratic Party and for liberalism, it will first have to resurrect a more positive vision of America's future than we find in The Road From Here.