BENJAMIN DISRAELI--TWICE PRIME minister of Great Britain, romantic novelist, inventor of modern conservatism--was a neocon in the plain sense of the word, a "new conservative" who began his career on the left. Conservative thinking dates to the dawn of organized society, but modern conservatism--a mass movement, a philosophy not for aristocrats and the rich but for everybody--was Disraeli's creation. That modern conservatism should have been invented by a 19th-century neocon is thought provoking. More surprising:His redefinition of conservatism is still fresh, and his political philosophy has never been more apt.

Conservatism is the most powerful and electric force in the American intellectual landscape. Young people no longer discover the left and get excited; they are far more likely to get their intellectual kicks discovering and experimenting with conservatism. But what exactly do conservatives believe? How do they resolve the seeming paradox that so many conservatives revere the past yet are also progressives, determined to move this nation forward and let it grow, stretch, and inhabit more and more of its own best self? Disraeli produced a definition of conservatism that resolves the problem. It is so terse and compelling, it ranks as a milestone of political thought.

He was a statesman who remodeled Europe and a thinker who examined some of the hardest of all political, social, and philosophical questions: How should democratic government work, what does party politics mean, where do the Jews fit in? I too "would lift up my voice to heaven, and ask," says the hero of his novel Tancred, "What is duty, and what is faith? What ought I to do, and what ought I to believe?" On these and related questions, Disraeli said fantastically improbable things that would be easy to dismiss except that many of them are true.

Like nearly all successful politicians, he was a fine actor and first-rate manipulator, accustomed to saying things he didn't necessarily (wholly) believe. Like nearly all brilliant men, he could be hard to read. Like all celebrated wits and superstar parliamentarians, he was a champion improviser, superb at making things up as he went along. For all these reasons, historians tend to forget his passionate sincerity on the topics he cared about most: Britain, the Jews, the Tories, the government of England. No man ever left behind so many pregnant thoughts for his followers, admirers, and professional interpreters to ignore.

He was born a Jew, but his father had him baptized at age 13 in a fit of pique. Disraeli the elder (who spelled his name Isaac D'Israeli) was angry with the local synagogue for insisting that he serve as an officer and fining him when he refused. Isaac was a modestly well-off literary man who published An Essay on the Manners and Genius of the Literary Character in 1795, and several collections of short pieces on a grab bag of topics, from "The Chinese Language" to "The History of Gloves." They were popular in their day and are still charming and readable, literary snackfood of a high order. Lord Byron admired D'Israeli, and called him the author "whose works in general I have read oftener than perhaps those of any other English author whatever."

Unlike his father, Benjamin was religious by nature. He became a devout Christian. But nearly everyone regarded him as a Jew, and he agreed: He was a Jew, except theologically. As Disraeli saw things, "Jew" was a race--to which he was ferociously proud to belong. ("All is race," he wrote; "there is no other truth.") Bismarck captured the world's attitude to Disraeli at his height. The Iron Chancellor was not easily carried away. But at the Berlin Congress in 1878, where Europe's top statesmen were gathered glittering at the summit of European history, and Disraeli dominated the proceedings, Bismarck said: "Der alte Jude, das ist der Mann"--The old Jew, that's the man.