Answer:
Military point: Battle of Gettysburg
Political point: 1864 Election: When. Abraham Lincoln won the Presidency
The concept was based on the Total siege of all southern coast
Explanation:
The Military turning point during the American Civil War was at the Battle of Gettysburg. This is a battle in which the Confederacy armies led by General Lee were halted by the Union and it stopped the advance of the Confederacy. Thereby Confederacy's chance of winning the war through military means took a turn.
Also, during the 1864 presidential election, Abraham Lincoln won against McClellan who appears to be in support of Southern slavery ideals and philosophy.
However when McClellan lost the election the hope of the Confederacy was dashed.
The concept on which Grant’s strategy to finally defeat the Confederacy and Lee was based on "Total siege of all southern coast." This drained the resources of the Confederacy armies under General Lee.
