5 8 The American Civil Warto gather their autumn harvest. The enemy
would have to follow him into Maryland,
thus sparing Richmond from a fresh Federal
advance. His presence above the Potomac
during the North's autumn elections also
might hurt the Republicans and bolster
advocates of peace. Moreover, if he stayed
north until late autumn, he might forestall
another Union offensive in Virginia until the
spring of 1863. Finally, his army's presence
might inspire slaveholding Marylanders to
flock to the Confederate colors. Although
Lee did not expect help from abroad, a
victory north of the Potomac could prove
decisive in persuading leaders in London and
Paris to extend formal recognition to the
Confederacy. Prime Minister Palmerston had
interpreted the Seven Days as evidence of
impending Confederate success, suggesting
to the Queen on 6 August that Britain
consider proposing an armistice in October.
The Army of Northern Virginia began
crossing the Potomac on 4 September 1862,
and events unfolded rapidly over the next
two weeks. Lee divided his army while at
Frederick, Maryland, on 9 September. He
assigned the majority of it to Stonewall
Jackson, who was to capture Harpers Ferry
(control of that point would give Lee a
secure supply line to the lower Shenandoah
valley) while Longstreet and the rest of the
army marched towards Hagerstown.
McClellan had followed cautiously. Lincoln
saw Lee's invasion as an opportunity to