Several disputes arose between President Abraham Lincoln and Congress regarding who had the responsibility to develop a Reconstruction plan for the South. According to Lincoln, the South had rebelled, not
According to Lincoln, the South had rebelled, not seceded.
Even though the Confederate States declared their independence from the US and formed their own country/government, Lincoln never formally recognized the Confederacy as an independent nation. This is why her refers to the war as the Civil War, showing that this is a war between two members of the same country.