Howard Zinn -- whose A People’s History of the United States, first published by Harper & Row in 1980, has sold some two million copies -- died last week at the age of 87. His passing has inspired numerous tributes to his role in bringing a radical, pacifist perspective on American history to a wide audience.

It has also provoked denunciations of Zinn as “un-American,” which seems both predictable and entirely to his credit. One of Zinn’s lessons was that protest is a deeply American inclination. The thought is unbearable in some quarters.

One of the most affectionate tributes came from the sports writer Dave Zirin. As with many other readers, he found that reading Zinn changed his whole sense of why you would even want to study the past. “When I was 17 and picked up a dog-eared copy of Zinn's book,” he writes, “I thought history was about learning that the Magna Carta was signed in 1215. I couldn't tell you what the Magna Carta was, but I knew it was signed in 1215. Howard took this history of great men in powdered wigs and turned it on its pompous head.” Zirin went on to write A People’s History of Sports (New Press, 2008), which is Zinnian down to its cells.

Another noteworthy commentary comes from Christopher Phelps, an intellectual historian now in the American and Canadian studies program at the University of Nottingham. He assesses Zinn as a kind of existentialist whose perspective was shaped by the experience of the civil rights struggle. (He had joined the movement in the 1950s as a young professor at Spelman College, a historically black institution in Atlanta.)

An existentialist sensibility -- the tendency to think in terms of radical commitment, of decision making as a matter of courage in the face the Absurd -- was common to activists of his generation. That Phelps can hear the lingering accent in Zinn’s later work is evidence of a good ear.

Zinn “challenged national pieties and encouraged critical reflection on received wisdom,” writes Phelps. “He understood that America’s various radicalisms, far from being ‘un-American,’ have propelled the nation toward more humane and democratic arrangements.... He urged others to seek in the past the inspiration to dispel resignation, demoralization, and deference, the foundations of inertia. The past meant nothing, he argued, if severed from present and future.”

I've spent less time reading the fulminations against Zinn, but they seem like backhanded honors. When a historian known for saying good things about the Fascists who won the Spanish Civil War considers it necessary to denounce somebody, that person’s life has been well-spent.

Others have claimed that Zinn did not sufficiently denounce Stalinism and its ilk. The earliest example of the complaint that I know came in a review of People’s History that appeared in The American Scholar in 1980, when that magazine was a cultural suburb of the neoconservative movement. The charge has been recycled since Zinn’s death.

This is thrifty. It is also intellectually dishonest. For what is most offensive about Zinn (to those who find him so) is that he held both the United States and the Soviet Union to the same standard. He even dared to suggest that they were in the grip of a similar dynamic.

“Expansionism,” he wrote in an essay from 1970, “with its accompanying excuses, seems to be a constant characteristic of the nation-state, whether liberal or conservative, socialist or capitalist. I am not trying to argue that the liberal-democratic state is especially culpable, only that it is not less so than other nations. Russian expansionism into Eastern Europe, the Chinese moving into Tibet and battling with India over border territories -- seem as belligerent as the pushings of that earlier revolutionary upstart, the United States.... Socialism and liberalism both have advantages over feudal monarchies in their ability to throw a benign light over vicious actions.”

Given certain cretinizing trends in recent American political discourse, it bears stressing that Zinn here uses “liberalism” and “socialism” as antonyms. A liberal supports individual rights in a market economy. By any rigorous definition, Sarah Palin is a liberal. And so, of course, is Barack Obama, who can only be called a “socialist” by an abuse of language. (But such abuse is an industry now, and I feel like Sisyphus just for complaining about it.)

The most substantial critique of A People’s History remains the review by Michael Kazin that appeared in Dissent in 2004. Kazin’s polemic seems to me too stringent by half. Zinn's book is not offered as the last word on the history of the United States, but as a corrective to dominant trends. It is meant to be part of an education, rather than the totality of it.

But Kazin does make points sometimes acknowledged even by the book’s admirers: “Zinn reduces the past to a Manichean fable and makes no serious attempt to address the biggest question a leftist can ask about U.S. history: why have most Americans accepted the legitimacy of the capitalist republic in which they live?”

That is indeed the elephant in the room. Coercion has certainly been a factor in preserving the established order, but persuasion and consent have usually played the greater part. Any American leftist who came of age after Antonio Gramsci’s work began to be assimilated is bound to consider hegemony a starting point for discussion, rather than an afterthought.

But Zinn was the product of an earlier moment -- one for which the stark question of commitment had priority. A strategic map of the political landscape was less urgent than knowing that you stood at a crossroads. You either joined the civil rights struggle or you didn’t. You were fighting against nuclear proliferation or the Vietnam War, or you were going along with them. It is possible to avoid recognizing such alternatives -- though you do end up making the choice between them, one way or the other.

There were subtler interpretations of American history than Howard Zinn’s. Anyone whose understanding of the past begins and ends with it has confused taking a vitamin for consuming a meal. But that does not make it worthless. The appreciation of complexity is a virtue, but there are times when a moment of clarity is worth something, too.