Almost exactly five years after it reached its zenith with the invasion of Iraq, the influence of neo-conservatives has waned sharply in Washington, as their nemeses, the "realists" in the national security bureaucracy, have increasingly asserted control over U.S. foreign policy.

While battered, however, neo-conservatives have not yet been forced from the field. And while their hopes that President George W. Bush would "take out" Iran's nuclear programme before leaving office appear to have diminished substantially, their hawkish voice is still heard loud and clear both in the White House -- courtesy of Vice President Dick Cheney's office and Deputy National Security adviser Elliott Abrams -- and in this year's Republican presidential race, where neo-conservative favourites include former New York City mayor Rudy Giuliani, Sen. John McCain, and, until earlier this week, Fred Thompson.

Indeed, as pointed out in Jacob Heilbrunn's new book "They Knew They Were Right: The Rise of the Neocons" (Doubleday), the neocons, despite the fiasco in Iraq, are already trying to detach themselves from both Bush and the Mesopotamian adventure they so avidly championed and entrench themselves ever more deeply into institutional Washington.

"Whether it's the Foundation for the Defence of Democracies or the National Endowment for Democracy, the Weekly Standard or the New York Sun, the neoconservatives are battle-hardened fighters who have created a permanent base for themselves. They will not disappear," according to Heilbrunn, a former neo-conservative himself and senior editor at the Nixon Centre's The National Interest journal.

Heilbrunn's much-anticipated book, which coincides with the publication of a not entirely unsympathetic biography entitled "Prince of Darkness" of the movement's most influential hard-liner, Richard Perle, affirms a number of central truths about neo-conservatism that are generally ignored or avoided in mainstream discussion of what he correctly calls a "mind-set" rather than an "ideology."

First, neo-conservatism "is in a decisive respect a Jewish phenomenon," even if many adherents -- albeit a minority -- are not Jewish and even if, it should be added, most U.S. Jews are not neo-conservatives. Moreover, neo-conservatives, both Jew and gentile, are bound by a "shared commitment to the largest, most important Jewish cause: the survival of Israel."

Second, its substance is largely determined by the lessons its followers draw from what they see as causes of the Nazi Holocaust: the alleged failures of German "liberals" in the Weimar Republic to stand up to the twin challenges of Nazism and Communism and of the western European liberal democracies to stand up to Adolf Hitler in the run-up to World War II; and the necessity of having overwhelming military power to crush any new Hitler pre-emptively.

As Heilbrunn, whose Jewish father fled Germany before the war, correctly notes, neoconservatives "see new Munichs everywhere and anywhere" -- a reference to the 1938 Munich pact by which Britain and France tried to "appease" Hitler by ceding part of Czechoslovakia to Germany.

Indeed, it is characteristic of neo-conservatives to depict virtually every foreign policy challenge -- from the Sandinista government in Nicaragua 25 years ago to Iranian President Mahmoud Ahmadinejad -- to U.S. (or Israeli) hegemony as a potentially cataclysmic replay of the 1930s. The neo-conservatives, according to Heilbrunn, "have shaped a romantic narrative for themselves in which they are the new Churchills staring down the forces of evil."

Fear that Saddam Hussein intended a "second holocaust" against Israel served as one of the main motivations for the neo-conservative promotion of war with Iraq, according to Heilbrunn. "As Jews, they (and their Catholic conservative allies) were haunted by the memory that the allies had not stopped the Holocaust -- and they strongly believed that it was America's obligation to act preemptively to avert another one."

Third, the movement's Trotskyist roots -- incarnated by its "founding father, Max Shachtman -- among the Jews from Central and Eastern Europe in the first half of the 20th century not only imbued its members with a distrust, even a hatred, of liberalism (despite their latter-day purported embrace of democracy promotion). They also largely shaped their polemical and political tactics, even as they moved rightward -- into the Democratic Party after World War II and thence, after the traumas of the 1960s and early 1970s, including two Arab-Israeli wars --- into Ronald Reagan's Republican Party.

"Their fling with Trotskyism [endowed] them with a temperament as well as a set of intellectual tolls that many never completely abandoned -- a combative temper and a penchant for sweeping assertions and grandiose ideas." The fact that they see themselves as "a kind of aristocratic intelligentsia," according to Heilbrunn, derives from their Trotskyite origins.

Fourth, "the social exclusion experienced by Jews at the hands of the WASP (White Anglo-Saxon Protestant) elite" that persisted in the U.S. into the early 1960s stirred a "deep resentment" among many of the movement's most influential leaders, notably Irving Kristol and Norman Podhoretz.

Indeed, Podhoretz, who edited Commentary magazine from the early 1960s until the mid-1990s and now advises Giuliani, sees the movement as the war against the "WASP patriciate", according to Heilbrunn.

Neo-conservatives "know that they will never be accepted by the establishment," he writes in a passage about Perle. "Indeed, they outwardly revel in the knowledge that they are outsiders. But beneath the veneer of confidence is a seething rage at the government bureaucracy and social elites."

These insights are the strongest part of the book, but, unfortunately, virtually all of them are made within the first 100 pages.

A lapsed neo-conservative himself, Heilbrunn offers useful, if unoriginal, accounts of the influences of German-Jewish philosopher Leo Strauss and military strategist Alfred Wohlstetter on the movement and its worldview. But he gets lost in his recounting of the evolution of the neo-conservatism and its various factions -- particularly the supposed divides between the Straussean/realist wing led by Irving Kristol and Jeane Kirkpatrick, on the one hand, and the Podhoretz-Abrams wing -- from the moment it first enjoyed power during Ronald Reagan's first term to the disastrous aftermath of the Iraq war.

While the reason for the subsequent incoherence of his account was probably due to deadline pressures and poor editing, it may also be attributable both to the ideological contortions of the neo-conservatives themselves and to the disappointing fact that Heilbrunn accepts and endorses the narrative of their own history. Indeed, his descriptions of liberal or left-wing foes, from the New Left and the Black Power movement to Democratic politicians, such as George McGovern, Jimmy Carter, and even Bill Clinton, echo those of the most radical neo-cons.

Thus, Clinton's first national security adviser Anthony Lake and secretary of state Warren Christopher "apparently saw the United States, not its enemies, as the main problem in the world." And had the 1998 Iraq Liberation Act, "which funneled money to ...Ahmed Chalabi ...been heeded [by Clinton], it might have helped avoid the chaos that the toppling of the Saddam Hussein created."

Ultimately, Heilbrunn is critical of the neoconservatives, but he accepts much of their worldview.

While Heilbrunn’s book is probably the best in the latest crop to explore the neo-conservative, the most comprehensive account of neo-conservative thinking remains "The Neoconservative Vision: From the Cold War to the Culture Wars" by Mark Gerson, a member of the board of directors of the defunct Project for the New American Century.