There's no way to test the hypothesis that only war would have ended slavery in the South, is there? You may be right, Greg F.. Blacks were certainly a smaller portion of New York's population than of South Carolina's, and so it was doubtless easier to free New York slaves.
Greg F. can correct me on this, but I was under the impresion that slaves were not a tiny proportion of Brazil's population. Yet they were freed without a fratricidal war. I didn't think serfs were a small portion of Russia's population, yet they seem to have been emancipated without St. Petersburg ordering Moscow burnt to the ground. I thought Blacks were a large portion of South Africa's population, yet I don't recall that apartheid was ended by Natal smashing the Transvaal or crushing the Orange Free State. I thought there were a lot of thralls in Scandanavia, but I somehow missed that it took war between Norway and Sweden to free them. Maybe I missed those wars.
And maybe Bobert et al have it right. Maybe it is not at all prejudiced to say of Southerners that, as long as a particular television channel exists, "there is really no pressures being put on them to behave like real human beings". They are just stupid, those Southerners, James Madison, Thomas Jefferson, George Washington, Bill Clinton, Jimmy Carter, Ralph Stanley,Woodrow Wilson, Harper Lee, Truman Capote, Woodie Guthrie, Flannery O'Connor, Stephen Foster, Matthew Fontaine Maury, Light Horse Harry Lee, Bobert...well, maybe not Bobert, and maybe not Bill Clinton, but it is certainly NOT prejudiced to say that Southerners are stupid. Barely human, they are snaggled-toothed hate-preaching creatures from the lower end of the gene pool, in denial, parasites, those Rednecks even call people insulting names.