<P> The American Civil War ( commonly known as the `` Civil War '' in the United States ) was fought in the United States from 1861 to 1865 . The result of a long - standing controversy over slavery , war broke out in April 1861 , when Confederates attacked Fort Sumter in South Carolina , shortly after Abraham Lincoln was inaugurated . The nationalists of the Union proclaimed loyalty to the U.S. Constitution . They faced secessionists of the Confederate States of America , who advocated for states ' rights to perpetual slavery and its expansion in the Americas . </P>
who started the civil war in the united states
Confederates