Anyone who has read about the Richmond Campaign of spring '62 has wondered about Secretary of War Edwin Stanton's closing of recruiting stations nationwide as the campaign got underway. From recent reading I see that this act, insane on its face, represents a piece of deep bureaucratic politics.
For a summary of ACW recruiting and replacement, we can't do better than this, written by Maj. Don Vandergriff:
The Union and Confederate armies used different methods in their attempts to sustain units. The Confederates in early 1862 adapted a system similar to a European depot system: They kept the number of their regiments low, and fed in replacements from the same geographical region. The intermissions between campaigns were the equivalent of a program to periodically rotate units back from the line - and veterans had time to integrate the "newbies" into their units prior to the next campaign.
This kept their regiments stronger - and more effective - until the mid-summer of 1864, when the Confederacy literally ran out of replacements.
In contrast, the Union continually raised new regiments at the demands of governors who wanted to reward political patronage by providing supporters with regimental commands. As a result, several times during the war these new regiments would go through a terrible bloodletting as both the leaders and the led experienced combat for the first time. Later in the war, the Union did ensure that the recovered wounded and sick were returned to the same regiment. But, the system was so wasteful that Gens. Ben Butler and William Tecumseh Sherman pleaded for its replacement with a "French depot system."
In reading William Hesseltine's Lincoln and the War Governors, I noticed that the Union recruiting stations Stanton ordered closed (all of them) were also operating on what Vandergriff here calls a depot basis; they were regional and they were replenishing state units with fresh local recruits, as was the case with the Rebels. By closing the recruiting offices, Stanton actually quashed this depot system established by Cameron, Scott, and McClellan; in a few months, when recruiting was reinstated under Stanton's design it went into effect as a state-based "new regiments only" program.
When Butler and Sherman asked for a depot system, they were actually asking for the restoration of the depot system that had been in effect throught the first quarter of 1862.
Most campaign historians note that Stanton closed the recruiting offices but are at a loss for motivation. It seems to me that closing the recruiting offices might have been about changing the replacement system before waves of combat losses could imbed the depot system in the machinery of war.