Robert Toombs, Jefferson Davis's Secretary of State, made the following statement
during a Cabinet meeting on 9 April 1861:
Concerning Ft Sumter, "The firing on that fort will inaugurate a civil war greater than
any the world has ever seen. It is unnecessary, it puts us in the wrong. It is fatal."
His warning on the 9th of April would come true in just 4 days, when the the Federal garrison at Ft Sumter, South Carolina, would surrender to Confederates after 34
hours of bombardment.
Although the general public in 1861 (as well as the general public in 2001) was
ignorant as to who had really initiated the hostilities,
Lincoln and others knew.
The Pittsburgh Daily Gazette openly admitted that "Lincoln used Ft Sumter to
draw the Confederate fire" and that Jefferson Davis and his subordinates
"ran blindly into the trap."
Presidential secretaries and Lincoln biographers John G. Nicolay and John Hay
admitted that the episode was ordered so that "the
rebellion should be put in the wrong."
Lincoln told his friend Senator Orville Browning, "The plan succeeded. They
attacked Sumter--it fell, and thus did more service that it otherwise could."
So began the revolution to destroy the Constitutional Republic.

It was not just Southern generals who owned slaves - northern generals owned them as well. A good example is General Ulysses Grant; his's slaves had to await until the Thirteenth Amendment for freedom. When asked why he didn't free his slaves earlier, Grant snidely relied, "Good help is so hard to come by these days." Grant served under the U.S. flag.