It is one of my "givens" that the Union armies were, by and large, organized by Republican ward-heelers and they represented fairly well some aspect or other of their local Republican Party political machines. There are a few minor exceptions to this.
Review the correspondence between Lincoln and Sickles, Lincoln and Butler, Lincoln and McClernand, Lincoln and Logan, on the subject of raising Democrat regiments to contribute to the Republican war effort. See especially the correspondence between Butler and Gov. John Andrew about Massachussetts commissions in Butler's early war recruiting drive.
I tend not to voice this opinion much, given the prevalence of what Ayers calls the "nationalist" interpretation of the Civil War and those rosy hues surrounding "Mister Lincoln's Army." Was very pleasantly surprised to hear Richard F. Miller talk on similar lines in the third segment of his interview on Civil War Talk Radio. A couple of his points:
* Read your state records and understand that military appointments followed patronage forms, especially from 1861-1862.
* A state commission must be understood as an explicit act of political patronage.
* Governors did not begin to worry about casualties or losses caused by incompetent appointments until public outrage forced the issue later in the war.
The most horrifying part of the interview was the disclosure that the 20th Mass. officers, stymied in promotion due to the shrunken size of their command, imported German men from abroad to fill out the regiment so that their career paths could be "normalized."
Stark. But that is the Civil War that I know. Hear for yourself.