On June 1, 1950, when the United States was gripped by fears of nuclear war and treason, when demagoguery was being practiced on a scale unparalleled in our history, one bright moment pierced the darkness.

The only female member of the U.S. Senate at that time, Margaret Chase Smith, quietly moved down the aisle and began to address her colleagues. She had drafted a speech she called a Declaration of Conscience and was gratified that six fellow Republican colleagues had allowed her to announce that they concurred. She delivered what, more than a half century later, remains one of the most remarkable political addresses ever heard in that “often-mocked senatorial ‘cave of winds.’” Simply, directly and eloquently she rebuked Senator Joe McCarthy and pronounced the dangers of McCarthyism.

A moderate Republican from Maine, a backbencher who was quiet, reserved and dignified in dress and manner, Senator Smith had waited for two years for her more experienced colleagues to speak out against “something disturbing and frightening.” McCarthy had engendered a wave of fear in the capital—indeed, throughout the land—and only one other senator, Herbert Lehman of New York, had possessed enough courage to speak against the junior senator from Wisconsin, who had become the darling of J. Edgar Hoover, Richard Nixon and the emerging right-wing establishment.

When McCarthy claimed in a speech in Wheeling, West Virginia, on February 9, 1950, that he had a list of 257 communists working in the State Department, nobody knew what the reaction would be. Neither did they know the power of the senator’s megalomania or how many people would believe his lies. The names and the number of communists kept changing, and McCarthy kept lying and grabbing for power. The cautious and politically naive President Eisenhower would not take him on; he kept waiting for McCarthy to immolate himself.

Until McCarthy overreached during the nationally televised army- McCarthy hearings and was bested by the seemingly gentle but incisive Boston attorney Joseph Welch, the Wisconsin demagogue terrorized government, religion, education and virtually every other social structure in America. Even Senator Smith’s conscience-driven speech did not produce results. Her colleagues were so afraid of McCarthy and the increasing power of the right wing that they deserted her.

A Pulitzer Prize–winning journalist and author of five national best sellers, Haynes Johnson has written what is not only a brilliant history of the McCarthy era but also a warning about our present fears and political caution and about right-wing demagoguery. He cites the most important studies of McCarthyism, from Thomas C. Reeves’s The Life and Times of Joe McCarthy to Ellen Schrecker’s No Ivory Tower to William Manchester’s masterly history, The Glory and the Dream. And like Samuel Johnson, he has ransacked entire libraries in order to write his book.

Most of the volume is devoted to an account of the history and effects of the McCarthy era, but when Johnson finally draws parallels between that time and ours, the meaning of the title becomes clear: thanks to McCarthy and his present-day adherents, we continue to live in an age of anxiety. “Half a century later,” Johnson writes, “a considerable bloc of Americans still bear allegiance to McCarthy’s memory and remain devoted to his anticommunist (or, now, anti-liberal) cause.”

Fears following September 11, 2001, for example, parallel those of the cold war. After September 11, Johnson writes, “Americans, the most optimistic of people, now faced unnerving official terror warnings. . . . Their television screens broadcasted alerts. Their newspapers published emergency preparedness articles full of alarming instructions on how to protect themselves from biological, chemical or radiological attacks. Their government authorities, already vastly expanding the surveillance and interrogation of citizens suspected of being security risks, advised them to be on the lookout for terrorists.” Fifty-five years earlier America had been gripped by similar fears: fear of a cold war turning hot; fear of a Soviet Union that had detonated an atomic bomb, ending the U.S. monopoly on nuclear weapons; fear of traitors within who were stealing the fruits of victory. Civil defense shelters blossomed in American cities. Children were taught how to crouch under classroom desks, as if that would stave off the effects of nuclear attacks.

The parallels were also evident during the 2004 presidential campaign, about which Johnson writes, “At a time of momentous issues that will define the course of the nation for years, the campaign degenerated into charges that recalled Cold War–era red-baiting. . . . Even if the issues were raised, daily personal attacks and relentless negative commercials drowned them out.”

In the three nationally televised presidential debates, a number of important questions received short shrift. There was no discussion of the horrors at Abu Ghraib and Guantánamo Bay and in Afghanistan—how they happened, who was responsible, what steps were being taken to prevent their reoccurrence and whether the United States still supports the Geneva Convention protocols about humane treatment of prisoners. And the Bush administration’s assaults on civil rights received barely a mention.

Johnson contends that “in the end, the 2004 presidential election came down to three elements: Bush and the Republicans were far better at expressing what they stood for than the Democrats. . . . The specter of terrorism and concern over national security overshadowed every other issue. And most crucial, employing fear as a factor in gaining, or holding, political power works as well—or better—in the new millennium as in the old.”

Why? Because we live in a continuing age of anxiety, because no reputable politician dares speak from conscience, because caution pervades the land. McCarthy’s heirs know this, and because they move with alacrity and self-righteousness, they dominate and shape our future.

In the spring of 2005, former Senate majority leader George J. Mitchell of Maine recalled the lesson of Margaret Chase Smith’s courageous political independence as the Senate neared a vote on a proposal to unilaterally change Senate rules for confirming federal judges. Mitchell, a former federal judge himself, drew a parallel between the McCarthy era and the present bitter ideological battle as the conservative majority steps up its assault on the judiciary.

In The Irony of American History, Reinhold Niebuhr pointed out that Americans are never safe “against the temptation of claiming God too simply as the sanctifier of whatever we most fervently desire.” Niebuhr demanded both modesty about our virtue and “a sense of contrition about the common human frailties and foibles which lie at the foundation of both the enemy’s demonry and our vanities.” Haynes Johnson awakens us anew to that prophetic call.