After the battle of Chancellorsville the two foes resumed their former positions on the opposite sides of the Rappahannock. The Union armies moral was very low, after suffering another defeat, the Confederates hopes were, in the words of General Alexander, hopes had reached the highest point attained since the beginning of the war.
Lee's force had been increased by a large force of conscripts (The Conscription Act of 16 April).
Longstreet and his two divisions which had been absent at Chancellorsville had rejoined Lee, giving him 272 guns and 76,000 men.
The Army of the Potomac was reduced to 105,000 by battle losses and expiration of terms of service. Grant's force of 75,000 men had Pemberton's 30,000 men bottled up in Vicksburg, while Johnston's 25,000 men was at Canton.
Unless Johnston could be reinforced, or some action taken to force Washington to recall part of Grant's army, Vicksburg was doomed and the Mississippi would be lost.
On May 15 Beauregard suggested to Johnston a plan to submit to the War Department for a "brilliant" summer campaign. About the same date Longstreet when passing through Richmond on his way to rejoin Lee met Sec. of War Seddon with a similar plan.
Longstreet proposed that to take advantage of the interior lines of the Confederacy by transferring his two divisions, 13,000 men, via Lynchburg, Knoxville and Chattanooga along with Johnston's 25,000 from Mississippi and Buckner's 5,000 men from Knoxville to Murfreesboro where Bragg with his 45,000 men were engaged with Rosecrans and his 60,000 Yankees. Longstreet's plan then called for Lee to go west in person, take command and defeat Rosecrans, then to march on Louisville and Cincinnati.
General Alexander in his writing said he believed that if anything would cause Grant's recall from Vicksburg "it would have been this."
" The plan had greater chances of success then those involved crossing the bridgeless Potomac into the heart of the enemy's country, where ammunition and supplies would have to travel 200 miles by wagons, exposed to raids by enemy cavalry from either west or east. In this position, a drawn battle or a victory would leave us compelled to soon find our way back across the Potomac."
Davis was against Longstreet's plan from the start. Davis was obsessed in obtaining foreign intervention and believed that required a decisive victory of the AotP. .
After Longstreet reported to Lee he made the same suggestion, in Longstreet's own words "He reflected over the matter for several days and then fell upon the plan of invading the Northern soil, and so threatening Washington as to bring about the same hoped-for result."
Lee and Jackson had planned to try another invasion of Maryland, Jackson had gone so far as to prepare a large scale map of the country from Winchester to the Susquehanna, he even marked the location of farm houses with the names of owners, and if they were slave holders.
So there you have it, it wasn't Lee's plan, it was Longstreet's and will go down as another "what if?" question.