[PeaRidge]

Yes, money was the underlying prime factor until the battles became so messy in late '62, and early '63.
After the terror in Northern Virginia Lincoln had to shift public opinion away from Union failures and carnage. That is when he began to use the slave issue to turn the invasion into a crusade.

[hillyes]

Some good letters here: http://www.vmi.edu/archives/cwsource.html