Grant's overall strategy, up to the capture of Grand Gulf, had been
first to secure a base on the river below Vicksburg and then to
cooperate with Maj. Gen. Nathaniel P. Banks in capturing Port Hudson.
After this he planned to move the combined force against Vicksburg. Port
Hudson, a strong point on the Mississippi near Baton Rouge, was
garrisoned by Confederate troops after Farragut's withdrawal the
previous summer. At Grand Gulf, Grant learned that Bank's investment of
Port Hudson would be delayed for some time. To follow his original plan
would force postponement of the Vicksburg campaign for at least a month,
giving Pemberton invaluable time to organize his defense and receive
reinforcements. From this delay the Union Army could expect the addition
of no more than 12,000 men. Grant now came to one of the most remarkable
decisions of his military career.
Information had been received that a new Confederate force was being
raised at Jackson, 45 miles east of Vicksburg. Against the advice of his
senior officers, and contrary to orders from Washington, Grant resolved
to cut himself off from his base of supply on the river, march quickly
in between the two Confederate forces, and defeat each separately before
they could join against him. Meanwhile, he would subsist his army from
the land through which he marched. The plan was well conceived, for in
marching to the northeast toward Edwards Station, on the railroad midway
between Jackson and Vicksburg, Grant's vulnerable left flank would be
protected by the Big Black River. Moreover, his real
objective--Vicksburg or Jackson--would not be revealed immediately and
could be changed to meet events. Upon reaching the railroad, he could
also sever Pemberton's communications with Jackson and the East. It was
Grant's belief that, although the Confederate forces would be greater
than his own, this advantage would be offset by their wide dispersal and
by the speed and design of his march.
But this calculated risk was accompanied by grave dangers, of which
Grant's lieutenants were acutely aware. It meant placing the Union Army
deep in alien country behind the Confederate Army where the line of
retreat could be broken and where the alternative to victory would not
only be defeat but complete destruction. The situation was summed up in
Sherman's protest, recorded by Grant, "that I was putting myself in a
position voluntarily which an enemy would be glad to maneuver a year--or
a long time--to get me."
The action into which Pemberton was drawn by the Union threat indicated
the keenness of Grant's planning. The Confederate general believed that
the farther Grant campaigned from the river the weaker his position
would become and the more exposed his rear and flanks. Accordingly,
Pemberton elected to remain on the defensive, keeping his army as a
protective shield between Vicksburg and the Union Army and awaiting an
opportunity to strike a decisive blow--a policy which permitted Grant to
march inland unopposed.
With the arrival of Sherman's Corps from Milliken's Bend, Grant's
preparations were complete and, on May 7, the Union Army marched out
from Grand Gulf to the northeast. His widely separated columns moved out
on a broad front concealing their objective. When assembled, Grant's
Army numbered about 45,000 during the campaign. To oppose him, Pemberton
had available about 50,000 troops, but these were scattered widely to
protect important points. On the day of Grant's departure from Grand
Gulf, Pemberton's defensive position was further complicated by orders
from President Jefferson Davis that both Vicksburg and Port Hudson must
be held at all cost. The Union Army, however, was already between
Vicksburg and Port Hudson and would soon be between Vicksburg and
Jackson.
In comparison with campaigns in the more thickly populated Eastern
Theater, where a more extensive system of roads and railroads was
utilized to provide the tremendous quantities of food and supplies
necessary to sustain an army, the campaign of Grant's Western veterans
("reg'lar great big hellsnorters, same breed as ourselves," said a
charitable "Johnny Reb") was a new type of warfare. The Union supply
train largely consisted of a curious collection of stylish carriages,
buggies, and lumbering farm wagons stacked high with ammunition boxes
and drawn by whatever mules or horses could be found. (Grant began his
Wilderness campaign in Virginia the following year requiring over 56,000
horses and mules for his 5,000 wagons and ambulances, artillery
caissons, and cavalry.) Lacking transportation, food supplies were
carried in the soldier's knapsack. Beef, poultry, and pork
"requisitioned" from barn and smokehouse enabled the army which had cut
loose from its base to live for 3 weeks on 5 days' rations.
[Illustration: _Troops on the march, going into bivouac at night._
From a wartime sketch.]
A noted historian described this campaign: "The campaign was based on
speed--speed, and light rations foraged off the country, and no baggage,
nothing at the front but men and guns and ammunition, and no rear; no
slackening of effort, no respite for the enemy until Vicksburg itself
was invested and fell."