I received the following reply to my letter from Gen. Halleck,
WASHINGTON, D. C., August 22, 1863.
GENERAL: Your letter of the 11th instant is just received. The acceptances of yourself, Sherman,and McPherson have now all been received.
I have heard of no complaints whatever about the movements of your army since the fall of Vicksburg;on the contrary,everybody that it would require some rest before undertaking new operations. Your plain of moving against Kirby Smith from Natchez, by Harrisburg and Monroe,will agree very well with the line of operations suggested by General Banks,viz,to ascend the Red River to Shreveport and move on Marshall or to move from Natchitoches on Nacogdoches, Tex. This will make your two lines near enough together to assist each other. In case Banks adopts this plan, Kirby Smith and Magruder must abandon either Texas or Arkansas,or they will be obliged to wage a mere guerrilla war. General Banks has been left a liberty to select his own objective point in Texas,and may determine to move by sea. If so,your movement will not have his support and should be conducted with caution. You will confer on this matter freely with General Banks. The Government is exceedingly anxious that our troops should occupy some points in Texas,with the least possible delay.
In our contemplated operations in Arkansas and Louisiana,you will probably require additional cavalry. You are authorized to mount any of your infantry regiments,making requisitions on the proper department for horses and equipments. Your force should move as much as possible by water transports,in order to save land transportation trough a country where the roads are few and bad.
Very respectfully,your obedient servant,
H. W. HALLECK
The Papers of Ulysses S Grant, Vol 9, p 174-5
O.R., I, xxx, part 3, p 108-9