<P> Arthur M. Schlesinger, Jr. noted that the states' rights "never had any real vitality independent of underlying conditions of vast social, economic, or political significance ." He further elaborated: </P> <P> From the close of the nullification episode of 1832--1833 to the outbreak of the Civil War, the agitation of state rights was intimately connected with a new issue of growing importance, the slavery question, and the principal form assumed by the doctrine was that of the right of secession . The pro-slavery forces sought refuge in the state rights position as a shield against federal interference with pro-slavery projects...As a natural consequence, anti-slavery legislatures in the North were led to lay great stress on the national character of the Union and the broad powers of the general government in dealing with slavery . Nevertheless, it is significant to note that when it served anti-slavery purposes better to lapse into state rights dialectic, northern legislatures did not hesitate to be inconsistent . </P> <P> Echoing Schlesinger, Forrest McDonald wrote that "the dynamics of the tension between federal and state authority changed abruptly during the late 1840s" as a result of the acquisition of territory in the Mexican War . McDonald states: </P> <P> And then, as a by - product or offshoot of a war of conquest, slavery--a subject that leading politicians had, with the exception of the gag rule controversy and Calhoun's occasional outbursts, scrupulously kept out of partisan debate--erupted as the dominant issue in that arena . So disruptive was the issue that it subjected the federal Union to the greatest strain the young republic had yet known . </P>

How was the constitution linked to the start of the civil war