Historian Henry Brooks Adams (grandson of "Slave-Power" theorist John Quincy Adams) explained that the Slave Power was a force for centralization:
Between the slave power and states' rights there was no necessary connection. The slave power, when in control, was a centralizing influence, and all the most considerable encroachments on states' rights were its acts. The acquisition and admission of Louisiana; the Embargo; the War of 1812; the annexation of Texas"by joint resolution" [rather than treaty]; the war with Mexico, declared by the mere announcement of President Polk; the Fugitive Slave Law; the Dred Scott decision—all triumphs of the slave power—did far more than either tariffs or internal improvements, which in their origin were also southern measures, to destroy the very memory of states' rights as they existed in 1789. Whenever a question arose of extending or protecting slavery, the slaveholders became friends of centralized power, and used that dangerous weapon with a kind of frenzy. Slavery in fact required centralization in order to maintain and protect itself, but it required to control the centralized machine; it needed despotic principles of government, but it needed them exclusively for its own use. Thus, in truth, states' rights were the protection of the free states, and as a matter of fact, during the domination of the slave power, Massachusetts appealed to this protecting principle as often and almost as loudly as South Carolina.
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