Final answer:
Lincoln initially hesitated to abolish slavery in all states due to concerns over the legal authority. He focused on preserving the Union while balancing the complex issue of slavery, which was finally resolved with the adoption of the Thirteenth Amendment after his death.
Step-by-step explanation:
Lincoln was initially hesitant because he worried he did not have the legal authority to abolish slavery in every state. At the time, the Constitution did not explicitly give the federal government the power to directly abolish slavery within individual states, and such actions could be seen as exceeding presidential powers or infringing on states' rights.
Furthermore, before becoming president, Lincoln had emphasized his stance on maintaining the Union over interfering with slavery in states where it already existed. This hesitancy was a reflection of the political and constitutional uncertainties of the time, and the delicate balance Lincoln sought to maintain between preserving the Union and addressing the contentious issue of slavery. It was only through the passage of the Thirteenth Amendment, which came after Lincoln's assassination, that slavery was finally abolished in all states, cementing the legal foundation for ending this institution across the United States.