Who was a threat to the union in the civil war?

Aside from the obvious threat from the confederacy and Lee, the seccesion of border states was a major threat. Lincoln was hesitent to issue the Emancipation Proclaimation because he feared alienating the border states. These states were the buffer zone bettween the Confederacy and hte north. Lossing them would not only give the Confederacy more men, it would also shift the battle lines closer to Northern strong holds and the nations capitol.