Setting aside the more cut and dried resume material I have been presenting about corps commanders, let us explore - tentatively - what the first four corps commanders of the AOP might have represented in different lights.
As noted here previously, our understanding of military careers must be pegged to the rise and fall of individual patronage patterns within the Administration; that patronage must also be plotted on a graph of events that strengthens or weakens sponsorship; and it should be understood that Lincoln personally patronized few generals. This is the essential and inescapable meaning of his famous question to McClellan about being "strong enough" politically even with Lincoln's own help to put his boot on the throats of Sumner, Heintzelman, McDowell, and Keyes.
At the start of McClellan's first Richmond campaign, McClellan had passed out of the orbit of Salmon Chase and into that of Seward (see Welles' diary). Keyes was also Seward's client after joining Seward's Ft. Pickens adventure with Porter and Meigs. Had McClellan failed generally but Keyes kept clear of that failure, Seward could have guided McClellan's command into Keyes' hands.
Seward's second "star pupil," Banks, was also positioned for succession in case of a McClellan stumble. (Seward actually "helped" select Banks' staff and I believe the large number of McClellan's foreign aides represent favors granted to the State Department).
Likewise, Seward controlled the prospects of New York war Democrat John Dix: when Democrat Horatio Seymour won the Empire State's governorship, Weed and Seward developed a plan to take it back by running Dix as a fusion candidate against Seymour. Interestingly enough, it was Dix who ended Keyes career, relieving him on the Peninsula. Keyes, who weakens Seward's client Scott is himself done in by Seward's client Dix: court politics, anyone?
It should be remembered that Seward also sponsored the military bureau chiefs Thomas and Meigs. We find them later being directed by Stanton more than they were run by Cameron and this needs a comment, too.
When Seward's client Cameron left the War Department, Seward's confidant Stanton replaced him, promising his patron that he would be a second Seward within the cabinet. Despite his secret machinations with Chase and the Radicals against Seward, Stanton pretended loyalty to his benefactor into the later parts of 1862. This would have translated into Stanton's directing the military bureaus in a way that was conscious of these chiefs being Seward's "friends."
By the start of the first Richmond campaign, Seward had, through this network, a major influence the war in the East. How that played out is difficult to say and should be a focus in someone's future research. If McClellan had written the "Secret History" he promised after the war, we would know much more about how Seward influenced the war in 1862.
Note the transaprency in the case of Montgomery Blair's correspondence with Butler and Lyons, where we see a cabinet officer personally directing military operations. It is reasonable to believe different sponsors had different kinds of interactions with their military clientele.
Seward's exercise of this influence - if we could see it directly - would clarify some of the motivation behind sponsoring military careers. Of course, politicians are constantly "making friends" for mutual aid and observing politicians interact with Grant during the Johnson Administration, we see different types of proposed "payout" and "payback" schemes based on political "friendship" (and sponsorship).
Certainly Seward seems to have collected he most military chips in the run up to distribution of corps commands. A quick tour of the other hands in play
* Chase's stable included McDowell, McClellan, and Franklin through 1861 and then McDowell and Pope in 1862. In the early war, McDowell and Franklin represented a team styled "Chase's military cabinet."
* Montgomery Blair's clients included Lyons, Fremont, and Butler. Contrary to Centennial history, he does not become a sponsor of McClellan's career in 1862.
* Bates was connected with and may have sponsored Edwin Sumner, Sumner knowing him and having urged him on Lincoln as Secretary of War before the inauguration. Sumner also had the benefit of being a cousin of Senator Charles Sumner, as well as being a Republican and abolitionist.
* Heintzelman was the special project of the Radical Republicans in Congress, as we have seen.
* Stanton's efforts to set up Hitchcock as commander of the AOP and as a major player in Stanton's care failed in March 1862. His efforts to recruit Rosecrans actually backfired that summer, Rosecrans becoming an enemy of the Secretary.
* Grant and Sherman had powerful Congressional backers, though Grant may have had the support of Illinois' Gov. Yates as well.
* Porter's close association with and defense of Gen. Patterson after Bull Run isolated him and he became, like Buell, Lander, Meade, and many others a purely "military dependent" without significant political patronage.
* Hooker talked a brigadiership out of Lincoln we are told, and he seems to stand as a beneficiary of Lincoln's direct patronage. What is never related in ACW histories is that Hooker was well known to Lincoln's great friend Edward Baker and was, in fact, decisive in making Baker a Senator when he (Hooker) split the Oregon Democrats in a close election on war issues.
A complete description of the patterns of patronage has yet to be written, but the astute reader will be surprised at what can already be found in primary materials long available to the public. The deeper problem of how to use those materials to illuminate connections - without falling into the worst tendencies of conspiracy history - is a subject for some other day.