Lincoln's assassination put the future of the nation in question because he was seen as the glue holding the country together during the aftermath of the Civil War. Without his leadership and vision, people were uncertain about what direction the nation would take next. Additionally, the assassination caused widespread shock and fear, leading to concerns about potential unrest or further violence in the country.
make it informal
Lincoln getting assassinated made everyone wonder what the heck was gonna happen next to the country. He was like the main dude keeping things chill after the Civil War, so without him, people were like, "Uh oh, what now?" Plus, the whole nation was freaked out and worried about more chaos or fighting breaking out.
