No attempt was made to overthrow the US government. No plan was hatched to send assassins to Washington to kill President Lincoln. They simply wanted to form a new nation, founded upon the Constitution that they deemed to be violated. Lincoln wanted the to collect the tariffs that would be sent to the Congederate government, stated he had no intention nor legal right of interference in anything else, and sent warships to SC to takeover the ports. All this while LYING to former US Justice Campbell, the peace commisioners and his own cabinet. Just as I would shoot the invader crawling thru my window, the Confederacy defended themselves.
Re the killing of US troops, not one US soldier would have been killed if Lincoln hadn't sent them into the South to start the war.