LENIN OFTEN PREACHED against the armchair revolutionaries of his day, voicing his impatience with their "inclination to substitute discussion for action, talk for work, the inclination for undertaking everything under the sun without finishing anything." Obviously he was right--although the republican and communist revolutions of modern history have derived their inspiration in part from abstract theorization and radical principles, the forces that toppled the ancien regimes in both Europe and Asia depended primarily on the power politics and dogma that motivated insurgents among both peasantry and gentry.

It is ironic that Michael Walzer's chapter on the general historical patterns of revolutions emphasizes the political relationships between the intellectual vanguard and mass uprisings of the English, French, Russian and Chinese revolutions. His concern seems almost narcissistic--the former Harvard professor certainly fits the bill of today's radical intelligentsia. At least, he must conceive of himself as a bright light in the revolutionary vanguard. But Walzer is not so easy to pin down. He emphasizes that his writings have been for the most part politically motivated. Still, his most engaging work wanders into the realm of abstract generalities, indulging in the grandiose and ineffectual idealism that Lenin scorned.

A pacifist armchair radical extraordinaire, Walzer was militant enough to take to the streets in protest of the Vietnam war. His own paradoxical intellectual history parallels both the triumph and despair of the Left in this country over the past two decades. Those liberals whose idealism withstood the disillusioning '70s can only be passive in their concern for social justice--"working within the system" has replaced the passionate efforts to effect fundamental changes in society. A more just and egalitarian vision of the future seems like a faded dream, but the memory of the hope still remains.

Similarly, Walzer's ideas as a young radical intellectual evinced a sense of political urgency. His arguments may not have always been clearly reasoned, but they sparkled with the anticipation of a radically different and much better world. His maturation as he approached middle-age has involved a more staid and withdrawn perception of political realities, reverting to more abstract and idealistic conceptualization. He originally developed his ideas on morality in warfare to politicize his opposition to the Vietnam war. But the final product of this thinking, Just and Unjust Wars, was not published until 1977. A masterpiece of careful and intelligent ethical reasoning and comparative history, it did not have much practical effect. Richard Nixon, not the radical left, ended the war, only after megatons and countless civilian deaths.

Radical Principles, a collection of essays spanning Walzer's career, presents a dilemma to the reader who endorses the writer's early radical political aspiraitons. If his youthful writings have the nostalgic charm of historical value, his more recent essays are considerably more thought-provoking. Although he explicitly omits all writings on the war, the aspirations and politics of the radical movement--the New Left that derived much of its impetus from the war protest--serve as his preoccupying theme during the early '70s. This group of essays will surely disappoint most people who know Walzer as the serious and methodical Harvard political philosopher. His opinions included as much interpretation of American culture as of politics, reflecting the hectic transition of American society. Although often insightful and emotive, their desultory vagueness smacks of Harper's and Atlantic standard monthly pablum.

THE LATER ESSAYS, aimed primarily as a counter-offensive to the prevailing neo-conservative outlook, offer a soundly argued, albeit imaginative, confirmation of his socialist and egalitarian principles. Here, Walzer aptly flaunts his philosophical intellect, demonstrating the depth, precision and creativity to render some of his far-fetched notions plausible, if not convincing. His "In Defense of Equality" attacks arch-neo-conservative Irving Kristol's attempt to justify large-income inequalities as the natural product of a hierarchy of innate abilities. For Walzer, the moral claim to the products of society cannot depend on some specious ground of superior ability, but on specific human qualities and needs.

In "Town Meetings and Worker's Control." Walzer deceptively renews the time-honored social-contract tradition to state his theory justifying socialism in modern America. Just as an entrepreneur cannot own a city or stake claim to its political governance, neither should he be entitled to corporate ownership; economic enterprise, like political, involves human relations and cooperation that cannot be possessed by any group of individuals. His argument here is intriguing, but not really convincing, and a bit myopic. He conveniently ignores the emergence of a modern managerial class and bureaucratic power--although he devotes a great deal of attention to this in other essays. Nevertheless, his fable presents a useful and fresh paradigm for the moral justification of a socialist state.

NOT SURPRISING in light of the country's current political mood, Walzer seems unsure exactly how to make that state a practical reality. He vacillates in his essays between emphasis on revolution and on the extension of the current welfare state by the new class of technical specialists. He is also ambivalent toward the role of intellectuals like himself in creating the new society according to his principles. His wallowing exegesis on the failure of the intellectual Left to transform society during the past two decades sheds doubt on the efficacy of liberal ideas to influence the future.

Walzer's two most fascinating articles, both written within the past couple of years, deal directly with this question. The first, a serious theoretical attempt to analyze the common features of revolutions in the modern world, emphasizes the subordination of intellectuals to doctrinaire ideologues. The other article asserts the durability of a class of sensitive thinkers--Shelley's "unacknowledged legislators of the world"--in the face of the challenge of unflinching mandarin elites. Walzer, thus, justifies his own commitment to radical principles as the ground work for his passive vision of a just society. But he does not completely abandon the revolutionary zeal of his earlier years. In the '80s, he cannot reasonably expect to form an intellectual vanguard for a socialist revolution, but he can justify his moral theorizing with Rousseau's dictum--"If I were prince or a legislator, I should not waste time in saying what wants doing; I should do it, or hold my peace." Today's liberals ought to take Walzer seriously, for, perhaps, the principles are all they have left.