The Union and the Confederacy faced very different tasks in the war. The South had to defend its territory and force the federal government to halt military action. The North had a more complicated challenge. Initially, northern political leaders believed that secession was driven mainly by slave owners and that high death rates and destruction of property would only alienate southern whites who favored reconciliation. But a policy of conciliation depended on early Union victories. With early defeats, it was clear the North would have to invade the South and isolate it from potential allies abroad. At the same time, most northern politicians believed that the nation could be reunited without abolishing slavery while abolitionists argued that only emancipation could resolve the problems that led to war. Meanwhile, enslaved Southerners immediately looked for ways to loosen their bonds.