States' rights
States' rights theories gained strength from the awareness that the Northern population was growing much faster than the population of the South, so it was only a matter of time before the North controlled the federal government. Acting as a "conscious minority", Southerners hoped that a strict constructionist interpretation of the Constitution would limit federal power over the states, and that a defense of states' rights against federal encroachments or even nullification or secession would save the South. Before 1860, most presidents were either Southern or pro-South. The North's growing population would mean the election of pro-North presidents, and the addition of free-soil states would end Southern parity with the North in the Senate. As the historian Allan Nevins described Calhoun's theory of states' rights, "Governments, observed Calhoun, were formed to protect minorities, for majorities could take care of themselves."