Philip Roth is not famous for reticence and modesty — his personal habits seem to have earned him as many enemies as his vitriolic prose — but his latest novel glows with a moral righteousness, a clarity of purpose and a sense of urgency that sets it apart from earlier work like 1972’s “Portnoy’s Complaint.”

Roth’s extraordinary new novel, “The Plot Against America,” is the story of his childhood as a Jewish boy recast in an America where anti-Semite and Nazi sympathizer Charles Lindbergh is the 33rd president. In a memoir of what might have been, he recounts the increasingly intense persecution of American Jews, the development of fascism in the United States and the first American pogrom.

“The terror of the unforeseen is what the science of history hides,” Roth writes. “Everything unexpected in its own time is chronicled on the page as inevitable.”

This novel’s great strength is its foundation in a fictional reality that seems as plausible as the historical world described in modern textbooks.

Roth understands that the United States is a country built upon its immigrant population; the conception of racial purity that fueled Hitler’s mania could never have had the same appeal in America as it did in Germany. The American solution to the “Jewish Question” in the novel consists not of concentration and extermination, but in the decentralization of Jewish life in America. Rather than confining Jews to ghettoes or camps, the Lindbergh administration plans to scatter them throughout the gentile West and Midwest.

In the political rhetoric, this program is described as an effort to include Jews in American cultural life. The goal, of course, is the dissolution of Jewish culture in the United States and the destruction of the “Jewish conspiracy.” While these policies are executed in the same spirit as the race laws in Nazi Germany, the pretence of good will and the constant appeal to “American values” lend an unmistakable flavor of the familiar to Roth’s Orwellian alternate reality. The denunciation of dissenting Jews as “traitors” is particularly resonant in the current political climate.

The natural criticism is that Roth has a tendency to overdo it. His unflagging contempt for the masses and the demagogues who act as their shepherds becomes increasingly unpleasant as the novel proceeds. One could also suggest that he takes too many imaginative liberties and that he loses his focus at the end of the novel.

Part of the problem is that Roth feels compelled to state explicitly the various things he works so hard to imply. The language is raw and unadorned, and the effect is an awkward redundancy that becomes frustrating. However, it isn’t a style to which he’s bound by incapacity: It suits the narrator well — a character who is more interested in making himself heard than in presenting his story with any particular elegance. It seems to have been Roth’s intention to leave the story raw and unadorned.

In addition, the nightmare in Germany renders the criticism of exaggeration largely inadmissible. The fiction Roth invents is vastly less horrific than the fantastic and inconceivable tragedy of the Holocaust, and to suggest that America is incapable of the comparatively minor injustice perpetrated in this story is to succumb to the ignorance that made the Holocaust possible in the first place.

Whether his motivation for writing this book was political or imaginative, this is a subject close to the author’s heart. The self-mockery that earned him criticism from the Jewish community in the past is here transformed into a proud and sympathetic vision of a pardonably imperfect people. There are hypocritical, selfish, obsequious Jews in this novel, and there are Jews like Roth’s mother and father, whose conviction in their own beliefs remains uncompromised, and whose extraordinary strength gives the novel its hard beauty.

As with any story about the plight of Jews in World War II, this novel demands honesty and urgency, and Roth delivers both. The murder of the European Jews was a crime committed not by some demon risen from hell, but by human beings acting in accordance with the orders of other human beings. The success of the crime was contingent upon the collaboration of local governments in occupied countries, and Roth insists there is no reason to assume the United States would have conducted itself more honorably in the same position. This nation, after all, refused to accept Jews without restriction during the war.

The history of anti-Semitism in the United States is a fact that Roth does well to call to our minds in the present age. With a fundamentalist Christian in the White House and an ideologically bipolar population, he can only be commended for the uncompromising vehemence with which he does so. The pivot point that sends the United States down the Nazis’ road in this novel is the election of a “honest,” “patriotic” American. Roth warns us that just because it didn’t happen then doesn’t mean it can’t happen in the future.