He was only 26 years old when he set foot in America, an aristocrat by birth, a keen observer, a brilliant intellect, and a blessed writer. It was to get out of Paris in turbulent times and ostensibly to study the American penal system that Tocqueville and his travel companion Gustave de Beaumont made their extraordinary nine-month sojourn in America in 1831. But the work that he would produce — “Democracy in America” — is one of a handful of truly great books of political science and remains a profound guide to our modern democratic world.

Hugh Brogan’s “Alexis de Tocqueville” (Yale University Press, 736 pages, $35) is written with rare dignity, authority, and grace. Mr. Brogan informs us early on that he has been a student of Tocqueville for 50 years, having inherited the subject, so to speak from his father, Sir Denis Brogan, who wrote a short study of him.

Like some fine-looking confection from the corner patisserie. Mr. Brogan’s biography is a delight to the eyes but leaves a strange taste.

While the portrait of Tocqueville the man that Mr. Brogan sketches is charming, the author is not charmed, or even much impressed, with Tocqueville the political thinker. This is strange, given Tocqueville’s ferocious concentration on the urgent and fundamental questions of political theory. Surely Tocqueville was a man for whom his thought was the most important aspect of his life. But about Tocqueville’s thoughts Mr. Brogan is strikingly dismissive.

Throughout their American adventures, Mr. Brogan opines, Tocqueville and Beaumont simply ignored political parties and gave short shrift to Congress. They had no use for the company and conversation of women and wasted their time with too many lawyers. According to Mr. Brogan, Tocqueville never quite understood that in America elections check the abuse of power. Hence his “most serious mistake” was his idée fixe on the constitutional checks and balances on the abuse of majority power. Mr. Brogan, however, is generous: “Perhaps if he had been able to stay longer, he would have broken through.” But his generosity is misplaced, since “Tocqueville was as yet fundamentally mistaken about the nature of politics.” Despite dismissing most of Tocqueville’s thoughts about politics, Mr. Brogan concludes by declaring that “the Démocratie is the greatest book ever written on the United States.” We are left wondering why.

Mr. Brogan is even harsher about Tocqueville’s other masterpiece, “The Ancient Regime and the Revolution.” The work was incomplete at the time of Tocqueville’s death from consumption in 1859, and Mr. Brogan relays a marvelous anecdote. Striking his forehead, Tocqueville on his deathbed tells the nuns who were caring for him, “Oh! If you only knew all that was in there and how much I want to be cured so as to do my work.” But one suspects that even had the nuns cured Tocqueville, Mr. Brogan still would have dismissed him. “The accuracy of Tocqueville’s conclusions is of limited importance,” Mr. Brogan writes. Mr. Brogan describes Tocqueville’s portrayal of the Ancient Regime as “a medley of fiction and wishful thinking.” And this, because of his “commitment to obsolescent economic theory, his obsessive cult of property and his fear of revolution made him part of the problem which he analyzed.” Tocqueville was, according to Mr. Brogan, simply the victim of class prejudice. “Much of what he wrote can be understood as a personal manifesto,” he writes.

Mr. Brogan informs us that modern scholarship has refuted Tocqueville: that in France the towns were autonomous until the revolution was well under way and that local and civic life survived the Jacobins and the emperor. And hence it is simply “a Tocquevillian myth” that the Ancient Regime destroyed all the local liberties and institutions, leaving an empty space for the state to seize and progressively dominate.

But Tocqueville never says that. He is thoroughly alive to the fact that during many centuries the monarchy never ceased interfering, but he never tires of repeating how feeble and ineffective the monarchy’s attempts were. It is not “self-government” that was wounded but self-confidence and the social bond. By the time of Tocqueville’s death, the ancien regime had discredited itself as much by its hopelessness as by gross inequality.

The fundamental disagreement between Mr. Brogan and his subject concerns Tocqueville’s thought about the promise and problems of modern liberty. According to Mr. Brogan, Tocqueville is a partisan of the wrong sort of liberty, negative liberty. He fails to grasp what Mr. Brogan understands: that liberty is “a process” more potent than equality.

He would have us turn from the pages of Tocqueville to the painting of Eugène Delacroix to understand modern liberty. He deems Delacroix’s painting “Liberty Leading the People” more wise than anything Tocqueville ever said on the subject. In Mr. Brogan’s reading of the painting liberty must be destructive — on her march she “clears the way for rebuilding, and what is built in Liberty endures.” After the horros of the 20th century these words are truly staggering.

What Mr. Brogan is at great pains to deny is just how arresting, fresh, and relevant Tocqueville remains in the 21st century. Tocqueville’s question remains our question: Why is democracy so pervasive, and democratization so irresistible? His fundamental insight concerns the equality of conditions in modern society. The equality of conditions flows from democracy as a political regime, but it mysteriously breeds a democratic “social state” deemed separate from politics. In other words, democracy engenders a sense of independence in its citizens — that we are each a whole, depending on no one else. Democracy is thus more than a form of government — it nearly denies the need for government.

Despite his beautiful prose style and professed admiration for Tocqueville, Mr. Brogan gives his subject too little credit for understanding the problems that continue to haunt our politics. Whether we are trying to think about America today and its calls for democracy abroad or Europe and its dream of a democratic state beyond politics, Tocqueville remains our indispensable guide.

Mr. Doneson teaches at the Lauder School of Government, Diplomacy and Strategy in Herzliya, Israel.