You don’t have to agree with everything in this monumental account of politics in the 1960s and 1970s to find Rick Perlstein’s “Nixonland” (Scribner, 896 pages, $37.50) interesting and even engrossing. The book is a masterful retelling of the turbulent period between the crushing defeat of Barry Goldwater by Lyndon B. Johnson in 1964 and the equally stunning loss by George McGovern to Richard Nixon in 1972.

Mr. Perlstein’s use of the elections of 1964 and 1972 as ideological goalposts may be arbitrary, but it is easy to see why he selected them. Could two such different countries really be separated by eight short years? It was as if a great dam broke following Johnson’s election. He signed the historic Voting Rights Act on August 6, 1965, which led one observer to declare, “There is no more civil rights movement.” Five nights later, the Watts district in Los Angeles erupted in one of many major race riots to come. Drug taking, which had been largely confined to the ghetto and the cultural avant-garde, was mainstreamed and celebrated. A tiny antiwar movement mushroomed into a national mobilization campaign, involving the seizure of college campuses (Columbia University) and resulting in the shooting of student protesters (Kent State).

The liberal consensus — represented by Johnson’s triumphant performance in 1964, with 61.05 percent of the popular vote and 486 of 538 Electoral College votes — seemed to signal the country’s embrace of the great Democratic coalition built by Franklin D. Roosevelt. Two short political cycles later, that coalition was in tatters — a casualty of antiwar and countercultural excesses and the near absolute takeover of the party by elites devoted to a more radical extension of liberal policies than could be countenanced by the voters who normally animated Democratic turnout. The same Mayor Richard J. Daley who ruled the 1968 Democratic Convention with a famously iron fist was challenged for and finally denied a convention seat at the 1972 Democratic Convention in Miami. It must have been sweet revenge for the film stars and other glitterati who disdained Chicago’s “Boss,” but it came at a price. The Democratic Party had changed, and with it the shape of American politics.

“Nixonland” offers a rich and colorful account of that political sea change, but Mr. Perlstein’s remarkable research is assembled around a deeply misleading thesis — that the rise of Nixon heralded and defined the ideological divisions that have given us a red-state, blue-state political map ever since. Like most liberals, Mr. Perlstein labors under a misapprehension that Nixon was a political conservative. While he is too good a historian not to acknowledge some differences between Nixon and such movement conservatives as William Buckley and Ronald Reagan, he is usually stuck in the default position that ignores Nixon’s well-documented record.

This record’s highlights include wage and price controls in peacetime, decoupling of the dollar from gold, a 10% tariff on all imports into the United States, and the creation of a new and gigantic bureaucracy with the Environmental Protection Agency. He proposed a universal health care system as well, but Watergate got him first. Even his foreign policy, while it may have been adroit, was hardly conservative. Hindsight confirms that his historic embrace of China was the right thing to do, but it involved some shabby, if not dishonorable, treatment of Taiwan. The last American helicopters fleeing Saigon happened on his watch, and that wasn’t pretty. His slavish devotion to missile-control talks with Moscow and his generally nonconfrontational relationship with corrupt Soviet leaders may have prolonged the Cold War and certainly encouraged the Soviet fantasy that communism had a future. Small signals are often telling, and it is no coincidence that Pete Peterson, Nixon’s influential commerce secretary, went on to become one of the most vociferous critics of Presidents Reagan and George W. Bush.

If Nixon did not share the politics of the conservative movement, then perhaps, Mr. Perlstein suggests, he introduced to them an approach to campaigning that movement conservatives would make use of later. The author hangs much of his thesis on the so-called “Southern strategy,” through which the GOP won a large swath of white Southerners — a formerly reliable Democratic constituency — in the wake of the civil rights movement. But several recent books on this period, notably Conrad Black’s biography of Nixon, have found the president behaving generally honorably on matters of race. In fact, the drift of Southern whites to the Republican Party predated Nixon, and was first evident during the Truman administration, with the so-called “Dixiecrat” revolt. And while the phenomenon initially had unfortunate racial overtones, the transformation ultimately spoke much more loudly about the leftward drift of the Democratic Party, on a range of issues from abortion to national defense, than it did about race and prejudice in the South.

Some of the best writing in this book deals with the apocalyptic events that convulsed and shaped the 1960s and 1970s — the assassinations, riots, murders, protests, and convention dramas. Mr. Perlstein obviously has a deep knowledge of the period, and his portrait of the country in tumult offers far more depth and complexity than does his guiding thesis, that Nixon’s election was an essentially political victory for the right, and that it announced the triumph of conservatism.That triumph would come much later, in 1980, with the election of a far more genial and vastly more consequential president.

Mr. Willcox, a former editor in chief of Reader’s Digest, lives in Ridgefield, Conn.