Tracking a Continental Shift : THE INHERITANCE: How Three Families and America Moved From Roosevelt to Reagan and Beyond.<i> By Samuel G. Freedman (Simon & Schuster: $27.50, 464 pp.)</i>

The Silent Majority. Reagan Democrats. Angry White Men. Pollsters and politicians have affixed sundry names to the loose bloc of working-class ethnics of Democratic lineage who in the last 25 years have become rank-and-file conservatives. In “The Inheritance: How Three Families and America Moved from Roosevelt to Reagan and Beyond,” Samuel G. Freedman, a journalism professor at Columbia and a former New York Times reporter, tries to portray this social trajectory not just as a demographic trend but as a human saga.

Echoing “Common Ground,” Anthony Lukas’ magisterial account of three Boston families during the 1970s busing crisis, Freedman traces the journey of three Catholic families--one Polish, one Italian, one Irish--as they evolve over the generations from immigrants to New Deal partisans to middle-class suburbanites to Republican party loyalists. You might call it “Common Ground” meets “The Emerging Republican Majority.”

Freedman is not the first writer to illustrate this critical shift in American politics through a montage of personal stories. Jonathan Rieder’s “Canarsie: The Jews and Italians of Brooklyn Against Liberalism” and “Common Ground” itself both took their readers into the homes, schools and workplaces of their characters to illuminate the social forces that spawned their disillusion with welfare state liberalism.

Freedman’s account differs, however, in his exclusive emphasis on the key constituency of Catholics, who in the 1994 election cast ballots in numbers disproportionate to their size among the general population--and for the first time voted predominantly Republican.

If Freedman has obvious forerunners in this genre, he is nonetheless the first, to my knowledge, to attempt an account with this kind of cinematic sweep. His word-camera takes us to the gritty streets of East Harlem and the saloons of Fell’s Point, Baltimore; to the union hall of Local 86 in New Rochelle and the American Legion Post 1597 of Crotonville, N.Y.; to the Teenage Republicans summer camp in Bridgeport, Conn., and the barracks at Ft. Bragg--in a tour de force of research and reporting.

Each of Freedman’s three families follows a similar path: They begin cherishing liberalism’s largess and compassion and wind up smoldering at its perceived elitism.

Silvio Burgio, a plumber whose father immigrated to New York from Italy in 1890, owes lifelong gratitude to the unions. When he discourages his daughter, Lorraine, from chasing her dreams, she winds up as a switchboard operator; politically, she votes for Adlai Stevenson in 1952 but defects to the GOP by the late ‘60s. Her son, Frank Trotta, organizes patriotic rallies as a teenager in a rebuff to the counterculture, and he goes on to seek a career as a Republican election lawyer.

Meanwhile, Lizzie Garrett, a sweat-of-her-brow cleaning woman, leads her New York family through the Depression, worshiping FDR. Her son, Richie, the town’s gravedigger and an amateur fisherman, discovers his own attachment to the Democrats when the party fights against the polluters who sully his Hudson River. But Richie’s nephew, Tim Carey, gets drafted during the Vietnam War and is taunted by antiwar protesters. After his service, he goes to college, joins the Republican Party and ascends through the ranks as an operative.

Finally, the raffish Joseph Obrycki--an incorrigible gambler and glad-handing Democratic pol in Baltimore--passes his party loyalties to his daughter, Vilma. She cares passionately about civil rights and ending the Vietnam War. But her husband, Jack Maeby, a convert to free-market economics during his undergraduate days at Bucknell, influences their daughter, Leslie, who in turn becomes a GOP staffer in local politics.

The three stories converge at the State University of New York at Albany in the early ‘70s, where Frank Trotta, Tim Carey and Leslie Maeby throw themselves into Republican Party politics. Freedman’s epic culminates in the 1994 election of New York Gov. George Pataki, himself a Hungarian-American Catholic. Tellingly, he upsets incumbent Democrat Mario Cuomo--one of the last great embodiments of liberal ethnics whose passions still burn with the spirit of the New Deal.

The author braids his three strands with language that is richly descriptive (if at times a bit mannered) and with a keen eye for a dramatic scene. In less sure hands, his picture of the Garretts’ destitution during the Great Depression could have deteriorated into cliche.

But Freedman’s telling evokes Orwell: “Generosity was another name for doing more with less, redistributing literally pennies within the family budget. . . . Edward got hold of a secondhand rolling machine to save the cost of store-bought cigarettes. To keep enough food on the table, Lizzie made the hourlong trip by bus to the Italian section of Yonkers, which had the cheapest groceries around, and mastered the art of roasting the same chicken she had earlier boiled for soup.”

Likewise, he vividly and empathetically depicts the later generations struggling to get ahead, as they perceive government programs punishing the hard-working with taxes while rewarding the indolent with welfare checks and racial minorities with unmerited jobs. From the third generations’ point of view, their newfound affinity for the Republicans seems not a betrayal of family tradition but a logical calculation of self-interest.

Of course, maintaining such a high level of detail can be risky, and where Freedman is in doubt he chooses to add rather than subtract. At times “The Inheritance” digresses into the biography of a minor character or includes a mundane anecdote about an obscure state senate race, and the narrative starts to assume the pallor of a local news broadcast.

It is not faint praise, however, to say that if parts of “The Inheritance” bear the imprint of the Grapefruit School of History--which holds that what someone had for breakfast constitutes an important piece of information--the book never totters over the edge of irrelevance. Given Freedman’s ambitions, that balance counts for a lot.

Here’s why: While political history, in examining the movers and shakers of an era, doesn’t have to strain to demonstrate its importance, social history--the history of ordinary folks--faces a grim dilemma. On the one hand, to find a compelling narrative, the social historian must focus on selected individuals who may or may not be representative of some larger trend. Yet to establish the representativeness of his or her subject, the historian frequently has to present numbing statistical data that would bore nonprofessionals to tears.

Freedman steers deftly between this Scylla and Charybdis. He not only argues persuasively that the political transformation of American Catholics matters, he also shows in intimate detail how and why it happened.