By NICK KOTZ

After years of battling racial discrimination and braving state-sanctioned violence — with hundreds of Southern black churches set fire to and scores of citizens beaten or murdered for daring to challenge American apartheid — the civil rights movement achieved a climactic victory when President Lyndon Baines Johnson signed the Voting Rights Act on Aug. 6, 1965. It was the outcome of ”a shining moment in the conscience of man,” declared the Rev. Martin Luther King Jr. In less than two years, the nation did more to advance equal rights for minorities than at any time since Abraham Lincoln signed the Emancipation Proclamation.

The 1964 Civil Rights Act struck down the South’s segregation laws, outlawed employment discrimination and forbade discrimination in federal programs. For black Americans living in the South, the voting rights law finally secured the right to the ballot. And President Johnson initiated a sweeping new government policy called affirmative action. Its purpose was to overcome at least some of the accumulated human damage caused by 350 years of slavery and Jim Crow, and to ensure further progress toward equality.

Benefiting from that ”shining moment” in the 1960’s, a black middle class has prospered and grown rapidly. Yet millions of African-Americans remain mired in poverty in a nation bitterly divided over whether special help to minorities should continue. Affirmative action programs have long been under siege, vigorously attacked in Congress and the federal courts and criticized for ”discriminating” against the white majority. With conservatives dominating the federal government, civil rights groups and other liberal organizations have waged a mostly defensive battle to protect the gains of the 1960’s. Fresh ideas and effective leadership to advance the American ideals of equality and social justice have been in short supply.

Ira Katznelson, the Ruggles professor of political science and history at Columbia University, enters this fray with a provocative new book, ”When Affirmative Action Was White,” which seeks to provide a broader historical justification for continuing affirmative action programs. Katznelson’s principal focus is on the monumental social programs of Franklin Roosevelt’s New Deal and Harry Truman’s Fair Deal in the 1930’s and 1940’s. He contends that those programs not only discriminated against blacks, but actually contributed to widening the gap between white and black Americans — judged in terms of educational achievement, quality of jobs and housing, and attainment of higher income. Arguing for the necessity of affirmative action today, Katznelson contends that policy makers and the judiciary previously failed to consider just how unfairly blacks had been treated by the federal government in the 30 years before the civil rights revolution of the 1960’s.

This history has been told before, but Katznelson offers a penetrating new analysis, supported by vivid examples and statistics. He examines closely how the federal government discriminated against black citizens as it created and administered the sweeping social programs that provided the vital framework for a vibrant and secure American middle class. Considered revolutionary at the time, the new legislation included the Social Security system, unemployment compensation, the minimum wage, protection of the right of workers to join labor unions and the G.I. Bill of Rights.

Even though blacks benefited to a degree from many of these programs, Katznelson shows how and why they received far less assistance than whites did. He documents the political process by which powerful Southern Congressional barons shaped the programs in discriminatory ways — as their price for supporting them. (A black newspaper editorial criticized Roosevelt for excluding from the minimum wage law the black women who worked long hours for $4.50 a week at the resort the president frequented in Warm Springs, Ga.)

At the time, most blacks in the labor force were employed in agriculture or as domestic household workers. Members of Congress from the Deep South demanded that those occupations be excluded from the minimum wage, Social Security, unemployment insurance and workmen’s compensation. When labor unions scored initial victories in organizing poor factory workers in the South after World War II, the Southern Congressional leaders spearheaded legislation to cripple those efforts. The Southerners’ principal objective, Katznelson contends, was to safeguard the racist economic and social order known as the Southern ”way of life.”

Katznelson reserves his harshest criticism for the unfair application of the Servicemen’s Readjustment Act, known as the G.I. Bill of Rights, a series of programs that poured $95 billion into expanding opportunity for soldiers returning from World War II. Over all, the G.I. Bill was a dramatic success, helping 16 million veterans attend college, receive job training, start businesses and purchase their first homes. Half a century later, President Clinton praised the G.I. Bill as ”the best deal ever made by Uncle Sam,” and said it ”helped to unleash a prosperity never before known.”

But Katznelson demonstrates that African-American veterans received significantly less help from the G.I. Bill than their white counterparts. ”Written under Southern auspices,” he reports, ”the law was deliberately designed to accommodate Jim Crow.” He cites one 1940’s study that concluded it was ”as though the G.I. Bill had been earmarked ‘For White Veterans Only.’ ” Southern Congressional leaders made certain that the programs were directed not by Washington but by local white officials, businessmen, bankers and college administrators who would honor past practices. As a result, thousands of black veterans in the South — and the North as well — were denied housing and business loans, as well as admission to whites-only colleges and universities. They were also excluded from job-training programs for careers in promising new fields like radio and electrical work, commercial photography and mechanics. Instead, most African-Americans were channeled toward traditional, low-paying ”black jobs” and small black colleges, which were pitifully underfinanced and ill equipped to meet the needs of a surging enrollment of returning soldiers.

The statistics on disparate treatment are staggering. By October 1946, 6,500 former soldiers had been placed in nonfarm jobs by the employment service in Mississippi; 86 percent of the skilled and semiskilled jobs were filled by whites, 92 percent of the unskilled ones by blacks. In New York and northern New Jersey, ”fewer than 100 of the 67,000 mortgages insured by the G.I. Bill supported home purchases by nonwhites.” Discrimination continued as well in elite Northern colleges. The University of Pennsylvania, along with Columbia the least discriminatory of the Ivy League colleges, enrolled only 46 black students in its student body of 9,000 in 1946. The traditional black colleges did not have places for an estimated 70,000 black veterans in 1947. At the same time, white universities were doubling their enrollments and prospering with the infusion of public and private funds, and of students with their G.I. benefits.

Katznelson argues that the case for affirmative action today is made more effectively by citing concrete history rather than through general exhortations. Studying the New Deal, the Fair Deal, the Great Society and the civil rights movements of the 1960’s could not be more relevant at a time when the administration seems determined to weaken many of the federal programs that for decades have not just sustained the nation’s minorities but built its solid middle class. Whether or not Katznelson’s study directly influences the affirmative action debate, it serves an important purpose. With key parts of the Voting Rights Act set to expire in 2007 and other civil rights protections subject to change, we must understand a continuing reality: the insidious and recurrent racial bias in the history of American public life.

Nick Kotz, a journalist and historian, is the author of ”Judgment Days: Lyndon Baines Johnson, Martin Luther King, Jr., and the Laws That Changed America.”