Moreover, Great Britain had retained slavery after many other countries ended the practice. The end of slavery in Great Britain also meant that those in the North who wanted the abolition of slavery could support their assertions that the world viewed the United States as backwards and barbarous because of the practice of slavery. Moreover, it certainly changed the potential for allies in the Civil War. Though not a monarchy, the South was an aristocracy and both Britain and France were then-ruled by monarchies. As long as the struggle was about a states-right government rebellion, the root cause of that rebellion, slavery, could be ignored and European countries could provide aid to either side without real fear of repercussions. However, after Lincoln issued the Emancipation Proclamation, it was impossible for anyone to pretend that the war was about anything other than slavery. The governments in Britain and France could no longer aid the South without supporting the institution...

This meant that the Confederacy was without allies, and, lacking the manufacturing power of the North, this lack of allies meant that they would be technically inferior for the duration of the war.
Obviously, there is not one single point at which the Civil War became inevitable. In fact, although Lincoln's election was seen as the direct catalyst for succession, that is difficult to understand. Lincoln was anti-slavery, but had not run on an abolitionist platform. Had the Southern states not seceded, it is questionable whether Lincoln would even have tried to intervene in the issue of slavery. However, the fact that Lincoln was anti-slavery was enough to prompt secession. That makes it clear that it was the whole combination of prior events that dictated that major conflict was going to occur before the United States could settle into peaceful co-existence. To come into the modern world, the United States was going to have to deal with the issue of slavery.

References

Brotherly Love. (unk.). Historical document: Missouri Compromise. Retrieved February 22,

2011 from PBS.org website: http://www.pbs.org/wgbh/aia/part3/3h511.html

The Civil War Home Page. (2009). Events leading to war- a Civil War timeline. Retrieved from http://www.civil-war.net/pages/timeline.asp

Dred Scott v. Sandford, 60 U.S. 393 (1857).

U.S.History.org . (2011). Bloody Kansas. Retrieved from http://www.ushistory.org/us/31.asp