In most lines of work, a person does his credibility real damage by denying the obvious and asserting the manifestly untrue. Yet in the book world, there can be very large rewards for a writer who boldly turns reality on its head. With “White Protestant Nation: The Rise of the American Conservative Movement,” Allan J. Lichtman apparently hopes to claim some of those rewards for himself.

Lichtman’s thesis is embedded in his title: American conservatism should be seen as an ideology devoted above all to advancing “an antipluralistic ideal of America as a unified, white Protestant nation.” This breathtaking argument bumps into an obvious counterargument: What about all the Catholics? William F. Buckley, Rudolph W. Giuliani, Sean Hannity, Russell Kirk, Clare Boothe Luce, Joseph R. McCarthy, Michael Novak, Bill O’Reilly, Antonin Scalia, Phyllis Schlafly and William E. Simon hardly seem marginal to the past or present of American conservatism. Indeed, enumerating important Catholics in the American conservative movement feels a little like listing famous Jewish violin players. It might be quicker and easier to do it the other way around.

To the extent that “White Protestant Nation” aspires to be a work of history rather than a tract for the times, it has to be adjudged to have fallen well short of success.

Lichtman himself seems nervously aware of the wobbliness of his thesis. Immediately after advancing it, he acknowledges that conservatives have achieved a “partial and uneasy rapprochement” between white Protestants and white Catholics. Soon afterward, references to the title gradually cease, and then they vanish altogether.

By that point, however, Lichtman, a professor of history at American University, no longer needs it. His discarded title thesis has done the work required: given him a special personal definition of the term “conservatism” that allows him to trace the origins of the modern movement not to the anti-Communism of the 1950s or the opponents of the New Deal in the 1930s, as is usually done, but to the Ku Klux Klan of the 1920s. And not just to the Klan, but to all the other racialist and fascist groupings that troubled the peace of American society in the aftermath of World War I.

As Lichtman puts it: “American conservative politics is not about limited government, states’ rights, individual freedom or free markets. These are all dispensable ideas that the right has adjusted and readjusted to protect core principles.” And what are those core principles? They amount to “protecting America’s superior civilization from racially or culturally inferior peoples, foreign ideologies, sexual deviance, ecumenical religion or the encroachment of a so-called one-world government.”

For Lichtman, conservatism is less a body of ideas than a collection of unattractive impulses. No person or group that excites his ire is too obscure to be included as a vital component of the conservative story. Thus, in his telling, Elizabeth Dilling (who self-published conspiratorial anti-Communist and anti-Semitic books in the 1930s) is as integral to the origins of conservatism as Milton Friedman. Willis Carto’s Liberty Lobby deserves equal attention with Paul Nitze’s Committee on the Present Danger. And the racial theorists of the Pioneer Fund take pride of place over the University of Chicago economics department. This kind of unweighted cataloging will surely find an audience among the partisans of the activist left, where everything is connected and any stick will do to beat a dog. Yet to the extent that “White Protestant Nation” aspires to be a work of history rather than a tract for the times, it has to be adjudged to have fallen well short of success.

It fails, first, because assertion does not make things true. Lichtman dismisses the importance of free-market economics to conservative politics. But he offers scant reason for readers to accept a dismissal so at variance with general perception.

It fails, second, because Lichtman’s own intensely felt passions blind him to all contradictory evidence. He wants to denounce conservatives for Ku Kluxery and racism—and also for the administrations of Warren G. Harding and Calvin Coolidge, two presidents he intensely dislikes. Yet Harding was the first president in American history to publicly condemn lynching (in Birmingham, Ala., no less), and Coolidge denounced the Klan in a 1925 speech to the American Legion.

Likewise, the anti-New Deal Liberty League of the 1930s figures in Lichtman’s schema as blackly reactionary. The repeal of Prohibition is by contrast good and progressive. But the Liberty League was basically the old Association Against the Prohibition Amendment under a different name. Can these individuals (one of them a past chairman of the Democratic National Committee) really have been transformed from cosmopolitan libertarians to antipluralist reactionaries in the span of months? Or is it remotely possible that they saw some continuity between their past and present opposition to overweening government?

“White Protestant Nation” fails, next, because Lichtman lacks the historian’s intuition for change over time. He hails women’s suffrage as progressive and damns immigration restriction as antipluralist and reactionary. Yet many of the most important proponents of suffrage favored immigration restriction—and many of the pro-immigrant groups opposed suffrage. Advocates of racial equality like Norman Thomas could also be adamant isolationists; internationalists like J. William Fulbright could be determined segregationists. Facing this refractory reality, it might make sense to accept that the political alignments of the 2000s cannot easily be projected backward 70 years or more.

Perhaps the single most famous attempt to impose a white Protestant identity upon America was the State of Oregon’s effort to suppress Catholic schools, which culminated in a landmark Supreme Court case named for Walter Pierce, the Democratic governor who signed the legislation. During World War II, Pierce, by then a member of Congress, would favor the internment of Japanese-Americans. He was also a supporter of women’s rights, prison reform and New Deal economic legislation. So: Was Walter Pierce a liberal? Or a conservative? Or perhaps we should accept that once we voyage back in time, we arrive in a different political landscape, with issues not easily assimilated into our present-day controversies. Lichtman, like Gilbert and Sullivan, believes contrary-wise that every child born alive is born a little liberal or else a little conservative.

Finally, “White Protestant Nation” fails as history because Lichtman will not think seriously about the relationship between causes and effects. He is fascinated by what might be called the inner story, and so he mines archives and clippings for conservatism’s internal debates and struggles. But conservatism did not come to national political power in the 1980s by means of memorandums. It came to power because of the collapse of the governing liberal consensus of the 1950s and ’60s. Riots, crime, inflation, rising taxes, gasoline lines, recessions, foreign policy humiliation: it was these things that elected Ronald Reagan in 1980. The story of conservatism cannot be told in isolation from the larger political story. Yet Lichtman shirks that story—perhaps because to tell it would require him to engage the possibility that the liberalism of the ’50s and ’60s had ceased to work.

You do not need to be a partisan of a political movement to write its history. But you do need enough imaginative sympathy to comprehend how it won adherents and supporters. Yet increasingly it seems that the history of conservatism is attracting liberals who lack that sympathy—for whom the whole thing was a giant con, a tissue of rationalizations for ugly bigotries. These liberal chroniclers of conservatism refuse to examine their own prejudices. They do not see that their wholesale dismissal of the principles of others amounts to little more than self-flattery. We might call this the Bourbon school of liberalism: after many years in exile, it has still learned nothing.