Fear Itself: The New Deal and the Origins of Our Time. By Ira Katznelson. Liveright; 720 pages; $29.95. W.W.Norton; £22. Buy from Amazon.com, Amazon.co.uk

AT HIS inauguration, 80 years ago this month, Franklin Roosevelt addressed a nation gripped by fear. Liberal democracy looked like a spent force. Roughly 25% of the workforce sat idle. The middle class was in ruins. Elsewhere, dictatorships were casting liberalism aside.

America seemed close to its own revolution. “The situation is critical, Franklin,” said Walter Lippmann, an influential journalist, “You may have no alternative but to assume dictatorial powers.” Instead, as Ira Katznelson argues in an absorbing study that spans the period from Roosevelt’s first term to the end of the Truman administration, the result was an imperfect yet enduring system of separated government.

The New Deal is well-trodden ground. But according to Mr Katznelson, a political scientist at Columbia University, most historians overstate the influence of the executive. Apart from the first 100 days of Roosevelt’s presidency, when he drafted laws shoring up banking and boosting public works, it was Congress that transformed American government during a period of depression and war—and Congress that ultimately checked the president’s more expansive vision of a liberal state.

The most important congressional players in this period, argues the author, were southerners. After landslide Democratic gains, not only did their voting block make the New Deal a reality, but southern Democrats also dictated what it would do and whom it would most benefit. A few years later they provided vital support for America’s entry into the war. But their power had unpalatable roots, a direct result of disenfranchisement. Through poll taxes and other measures, the Democratic Party in the South, the only political force in the region, prevented most blacks (and poor whites) from casting ballots.

With no need to worry about electoral defeat, southern senators such as South Carolina’s Ellison “Cotton Ed” Smith and Mississippi’s Theodore Bilbo, a member of the Ku Klux Klan, gained seniority on important committees. Until the war intervened, two goals, one liberal, the other not at all, lay at the heart of their legislation: the economic development of their rural and desperately poor region and the preservation of racial segregation. Their greatest fear was the disintegration of the South’s carefully crafted racial order.

This meant that passing legislation often required Faustian bargains between southern and non-southern sections of the Democratic Party. Anti-lynching laws stalled and worker camps were segregated. The Social Security Act excluded farm workers and domestic staff, thereby excluding most black people from its benefits. Worried about empowering black GIs, John Rankin from Mississippi fought against suspending the poll tax for military absentee voters.

Rows over voting rights were harbingers of battles to come. But it was labour issues that first broke the Democratic coalition. Provisions that excluded farming from wage regulations and the right to unionise only delayed the inevitable. After the 1935 Wagner Act expanded union activity, southerners began to fear something new: the federal government. In response, they colluded with Republicans to rein it in, forming new alliances. Readers of this insightful book may feel that the past, albeit in new ways, lives on.