The primary advantage for the South in its 1862 offensive into Maryland was the demoralized state of many of the Northern troops in the opposing army, as well as the inexperience of the new recruits who had just been called up in order to make good on recent Union losses. Additionally, the outstanding leadership of General Robert E. Lee remained a key Southern strength.
To impress the British, who were on the point of granting recognition to the Confederacy and sending military aid.
Because he could.
Union
Antietam
Antietam
Stonewall Jackson's infantry occupied Frederick, Maryland on September 6, 1862. Soon after he was joined by General James Longstreet. This town played a big role in Lee's raid into Maryland.
Kentucky, Missouri, and Maryland all had stars on the Confederate flag but never officially joined.
By chance, McClellan had acquired a set of Lee's orders, revealing that his divisions were widely separated, and could be destroyed piecemeal.
Union
More money
Delaware Maryland
Maryland
Maryland did not join the Confederacy. However. as a border slave state (like Kentucky, Missouri, and Kansas) Maryland had individuals who fought for the Confederacy during the US Civil War.
A commanding General (Lee) who had built-up essential momentum after his string of victories in Summer '62. An enemy General who was looking increasingly hesitant and reluctant to attack. A good chance that Britain and France would grant official recognition to the Confederacy - if they succeeded in their invasion of the North. (And a few spies in the Union camp - though the other side may have had the same.)
break into 2 parts wit Western Maryland joining the confederacy
Delaware Maryland
Delaware Maryland
The Battle of Antietam was fought in Maryland on September 17, 1862. After the battle, Abraham Lincoln issued the Emancipation Proclamation, which freed all the slaves living in the Confederacy. This act dissuaded foreign states such as France and England, from coming to the aid of the Confederacy. Both countries had banned slavery and there were unwilling to ally with the Confederacy once the Union had tied their cause to the destruction of slavery.
Depends on whether you like Maryland or not...