Lincoln's assassination put the future in question because he was a popular and influential leader who had played a key role in guiding the country through the Civil War and towards the end of slavery. His death created uncertainty about who would lead the country in the post-war period and how they would handle the reconstruction of the southern states and efforts to reunify the country. Additionally, Lincoln's assassination highlighted the tension and division that still existed in the country, and raised concerns about the stability of the government and the safety of its leaders.
