Congress was completely ineffective in preventing the Civil War because the Southern states still seceded. This option is best drawn because of the fact that that in the case of the 2nd option, they did not delay the war in any way. It was only a matter of time until the war happened, and nothing could have stopped it from happening. Once the Southern states made the decision to secede, the war was inevitable.
I think it was Native Americans, I could be wrong though...
The border states during the Civil War were the slave states that didn't leave the Union. These states included Delaware, Kentucky, Maryland, and Missouri. Kentucky - President Abraham Lincoln considered Kentucky's loyalty to the Union as an important factor in the Union winning the Civil War.