symbolised the ideas of representative government, freedom, opportunity, etc.

Lincoln famously quipped that if he could preserve the Union without freeing a single slave, he would. However, how could the Union, or any representative government, exist if any party that lost a vote decided to pick up their ball and go home? Representative government requires cooperation, and that cooperation means continuing to to participate in the system even if you don't get your way.

There is also the matter of Lincoln's presidential oath. If one views the South's secession as illegal (or, if you rather, extra-legal), as Lincoln did, then the formation of secessionist governments was a direct challenge to the Constitution Lincoln swore to defend. In some states, particularly Virginia, there were considerably Union minorities that Lincoln was obligated to defend.

Finally, the South rushed to arms, preparing a military response to secession even before they fired the first shot of the war at Fort Sumter. Faced with open and violent rebellion, Lincoln used the powers available to him to do his job: uphold the Constitution and protect the nation.

The best book on the Civil War I've read is James McPherson's The Battle Cry of Freedom. My response is drawn from my reading off the book last week and the ensuing discussions of it led by my professor, Dr. Andrew Isenberg.

It's a very complicated topic and you could easily have several different answers, economics, tradition, power projection etc. Essentially, the South served as a buffer to the expansion of European Powers on the North American Continent. The British and French had been attempting to improve their strategic position in North America for some time. The British went so far as to offer the Republic of Texas a guarantee of sovereignty, military assistance, and economic aid if they would stay an independent republic as opposed to joining the US. The British were not doing this out of the kindness of their heart, it would give them a chance to exert influence on the continent and check US expansion. The US was aware of this and it was a primary motivating factor for the Tyler administration's hard lobbying for Texas annexation. During the American Civil War the French were attempting to conquer Mexico to accomplish the same aim. The Confederacy knew from the beginning that their existence depended on both foreign trade, and foreign alliances, they just did not have the population, resources, or war industry that the Union had. In the event of a settlement of some sort the Confederates would have needed military assistance from a foreign power to deter the US from continuing aggression. The US knew this and did not want to open the door to European presence on the North American continent as it threatened further expansion and the strategic position of the US. This is also why the US threatened France with war if it did not give up its Mexican adventure and was the purpose of the Monroe doctrine etc.

The two books that really touch on this are: One war at a time by Dean B. Mahin,

Abraham Lincoln and a new birth of Freedom by Howard Jones.

Tldr: The success of the Confederacy quite likely meant the creation of a weak state which could be used by European powers to further their interests on the continent at the expense of US interests.

Great question. I think you'll find many great answers in the FAQ.

One issue that I didn't find in the FAQ and rarely see in the arguments about the causes of the American Civil War is what I call the argument from why not? In 1861 cost benefit analysis of sending troops to preserve the Union would indicate a huge benefit with a relatively low cost.

Why would the Union allow the south to secede without any kind of a fight. The Union had greater manpower most of the military, and a mostly functioning central government. The south had some ideals a couple troops and a loose confederation of states. The war should never have taken 4 years and cost millions of lives. Union troops should have been able to defeat the confederate forces and march into Richmond by the end of 1861. With Virginia (the most influential southern state) in hand the Union should have been able to bully the remaining states into rejoining the Union.

Hindsight is 20/20. Today we know that the Civil War was a tremendously bloody conflict that redefined The United States of America. But in 1861 there was a huge chance that the secession of the south would be a minor blip in the history books. Something like.

The secession of 1861. "The southern caucus of states reacting to the election of abolitionist Abraham Lincoln formed a militia and attacked several forts. The legislatures of the southern caucus voted to secede from the Union and form a loose confederation of states. Abraham Lincoln acting decisively sent 60,000 troops to take the southern states capital of Richmond. After defeating the militia in several engagements the troops secured Richmond on October 10, 1861. The final southern state, South Carolina, officially ended it's resistance on Dec, 9th 1861."

But that's enough of my ranting. Please check out the FAQ for the really good answers.

I've always wondered whether it'd be feasible today to separate the North and the South...

Sorry, but I have removed this question because it appears to be in breach of Reddiquette. (It looks like you are attempting to drive views to your blog).