Why were many people suspicious of Lincolns successor new president Andrew Johnson?

Many people were suspicious of Andrew Johnson, Lincoln's successor, because he was a Southern Democrat who had opposed secession but remained loyal to the Union, raising concerns about his commitment to Reconstruction and civil rights for freed slaves. His lenient policies towards the South and lack of support for the Freedmen’s Bureau led to fears that he would undermine the progress made during the Civil War. Additionally, his frequent clashes with Congress, particularly with Radical Republicans advocating for stronger measures, further fueled skepticism about his intentions and ability to lead the nation through its post-war challenges.