Slavery;
Was embodied within the Constitution itself and was not even an amendment to the Constiution. However at least the 4th and 5th amendment supports the right of ownership of property and to compensation for the confiscation of such property, along with the 9th and 10th amendments which allowed the individual states themselves to decide the issue within their own borders. abolishionist were in violation of these assurnces under law.
Slavery and Control of Government;
Slavery I have already commented on. As for control of Governmment how in fact was the southern states going to be able to do that? Even with the 3/5 rule the South simplely did not have the population to offset the population of the northern states for repersentation in the House of Repersentatives. Only in the Senate was there even a close parity with the Northern states. This is demonstrated by the electorial college vote for Abraham Lincoln in which the 3 states of Pennsylvania, Ohio and New York completely neutralized the entire electorial college votes of all the 11 southern state. So how was the south going to be able to take control of the Government?
Two regions on seperate paths;
Is there anything wrong with that? Do we not have the freedom to pursue a different course in our lives that the next man? Or do we all have to develope the same way?
Slavery in the Territories;
This is a two edged sword. First in a free country would you not expect to be able to enjoy the use of your property anywhere. This is what the Dred Scott decision ruled that it was a right of a citizen to carry his SUV to California where they have different rules on auto emmissions. But also it was a threat in regards to the Territories not to the southern states, but to the Northern control of congress should the territories in the west become slave holding states.
"Bleeding Kansas"
Who was John Brown working for? Yes, the southern people reacted. what would you expect.
States Right
Can be summed up with following the rule of law. That is all that the southerners ask. A country that does not follow it own laws is not a country and does not deserve the respect of being called a country. Following the law is the only civilizing factor in any society and the only thing which seperate a mob from citizens.
Abolishionism
Lets say radical abolishionism. There were more abolishionist societies in the south prior to 1850 than there were in the north. Abolishion could have been accomplished without war had the law been followed as it was in Washington D.C. where slavery was outlawed by 1850. The southern state simply asked for the emancipation of their slaves in the same manner as England emancipated their slaves in the 1830's
Collapse of the two party system
To quote you, "Formed in 1854, as an anti-slavery party, the Republicans offered a progressive vision for the future", isn't a 'Progressive view of the future' what we are experiencing now? Isn't a progressive view thinking you have a better view or that you know better than other people? In other words I am smarter than you. THAT is why Laws are important. Laws are the commonly agreed to limits of man's conduct decided on by everybody, not just one person or a mob.
Election of 1860
was the total disenfranchizement of the entire southern states. Abraham Lincoln was not even on the ballot in the 11 states that became the Confederacy and as I said only 3 state in the north had enough electorial votes to counter the entire southern states vote. The question is How did Lincoln win such an overwhelming victory in ALL of the Northern state. Could you say election fraud? That is what the south thought. And what someone thinks is more important than the actual facts.
Secession Begins
When the ballot does not work, and the rule of law is not being followed, what else is there to do? Secession was the peaceful solution and was granted as a right by Thomas Jefferson under the Declaration of Independence. The Constitution does not superceed our nations "Birth certificate".
Finally a truely free people are not bound by the votes of people who would violate the laws of the land and those who wish to oppress them. Had the slaves rose up against the southern slave owners that would have been a different fight in 1861 But they didn't. The fight in 1861 wasn't to abolish slavery it was to "Preserve the Union" That is the oppression of the freedom of the southern states. When Lincoln declare that the war was being fought to free the slaves two years later, in 1864, 8,000 union soldier a month deserted* Grant's Army of the Potomac alone.
*Bruce Catton, Stillness at Appomattox