In the deeply polarized years following the American Civil War, this informed and engaging study contends, rumour and fearmongering stalked the land, continually destabilizing an already volatile national politics and rendering elusive the search for a new sectional rapprochement during Reconstruction. The tensions dividing a defeated and embittered Confederacy from the war's northern victors were genuine enough, and had a basis in actual experience. But everywhere these were exacerbated by the conspiratorial inheritance that Americans carried into the traumatic rupture of the mid-nineteenth century.

Mark Wahlgren Summers traces this paranoid style to the birth of American constitutional democracy. Fearful that their still-fragile republican polity was vulnerable to being toppled by backroom plotting and manipulation, public figures “shared in a general sense that there was a ‘true inwardness’” to politics, that there were “real menaces to the republic lurking” (4). In the evolving sectional crisis of the late antebellum years this outlook “attached itself” (15) to the controversy over slavery, and white Americans in both sections went to war equally certain in their conviction that a resort to arms provided the last and only hope for preserving constitutional government.

At the end of that bloody war, Summers argues, profound mutual suspicions inhibited a durable reconciliation. While ex-Confederates were especially inclined to an apocalyptic reading of the new circumstances, northern Republicans found it expedient to resort to hyperbole, a recurring manoeuvre that would eventually undermine their viability in the South. The heart of the study is the author's fresh and incisive rendering of the struggle between President Andrew Johnson and Congressional Republicans. A handful of prominent radicals took skilful advantage of the crisis in Washington to advance the cause of black freedom, Summers acknowledges, but the moderate core of the party was animated by more traditional concerns: in usurping authority for the executive, Johnson imperilled the republic. To the extent that his fall from power was not self-induced, it derived from a temporary convergence between quite distinct strands within Republicanism.

Though the study never adequately assesses the relation between manoeuvring at Washington and ground-level mobilization in the South, A Dangerous Stir does not confine itself to analysing high politics. Political agitation among the newly freed slaves – and the countermobilizations that their initiatives triggered among white southerners – figure prominently in two chapters. In “Black Scare” the author traces the deep roots of racial paranoia in the region, acknowledging the power of white southerners' “siege mentality” in shaping their hostility to emancipation and the federal power sustaining it. Rumour and fear repeatedly convulsed the region: whites felt themselves surrounded on all sides by “arsonists without number – or corroboration” (52), prophesying a “war of races” until, eventually, reality caught up with the vision, or nearly: the victims in this war were overwhelmingly black and the perpetrators nearly always white.

Summers returns again, in his final chapter, to a concise but forceful analysis of paramilitary confrontation. He pushes too far, perhaps, in emphasizing the Klan's ad hoc, cross-class, and intensely local character across the region – there was “no one actual conspiracy, just little conspiracies,” he insists (253) – but in compensation offers an important corrective to studies emphasizing freedpeople's agency: where tensions escalated into open confrontation, former slaves could seldom match the firepower available to their adversaries, many of whom were battle-hardened Confederate veterans. Federal resolve was therefore critical in sustaining Reconstruction, but the longer the crisis persisted the more difficult it became for northern Republicans to reconcile effective intervention with their reverence for constitutional methods.

The most provocative aspect of Summers's argument is his explicit challenge to the notion of Reconstruction as a “second,” “unfinished revolution,” an interpretive approach initiated by the progressive historians early in the twentieth century, but evident in W. E. B. Du Bois's Black Reconstruction and made explicit in the subtitle of Eric Foner's hugely influential 1989 study. Most white southerners and many northerners from across the political spectrum were anxious to restabilize American politics, the author contends; above all they wanted to avoid a new “revolution” and “save the Union with its republican institutions intact.” Continued instability, the recurring resort to extraconstitutional methods, posed the real threat to America's future, and the containment of the extraordinary tensions brought about by emancipation was in some sense a shared project. The assumption that Summers detects in much of the late twentieth-century historiography, that “the main purpose of Reconstruction” was to bring about a “second American revolution” (270), is in the author's view itself mistaken. Reconstruction did not fail, he insists; instead it succeeded in its central aim of restoring stable constitutional government.

A Dangerous Stir makes a significant and highly original contribution to the political history of Reconstruction regardless of the merit of its conclusions. Fleetingly introduced but never fully developed in the book's four-page coda, these seem extraneous to Summers's persuasive claim for the salience of rumour and fear in shaping events. Moreover, the focus on constitutionalism obscures and seems even to blind the author to the great paradox that Foner and others have identified in the outcome of these upheavals. The return to constitutional “normalcy” coincided with severe restrictions on the freedoms enjoyed by black southerners. To put it differently, freedmen and -women enjoyed greater freedom under conditions of military dictatorship than they did in the decades following the return to government by constitutional methods. Perhaps what was called for in the South in the mid- and late 1870s was much more, and not less, “extraordinary government action” (260).