Bit of a curious inversion - how would Abraham Lincoln have done during the Civil War had he been not Commander in Chief but just another political general fighting in the war?
Let's take as our POD that Seward gets nominated in 1860 and still wins the election (if he wins NY and all the states Lincoln won by reasonable margins, he can't exactly lose).
John Wentworth gets the VP spot, or some other western former Democrat - Seward declines to put Lincoln in the cabinet (Lincoln's own cabinet of opponents was rather atypical) - and the former Rep. and would-be President is left sitting around with very little to do when the Civil War starts.
At some point in the war, Seward ends up short on political capital and prevails on his former rival to accept a military appointment "for the good of the country" - and there is at the least a significant chance of Lincoln accepting.
When/where/to what is he likely to be appointed, and how does he do as a military officer?
It needs to be noted that the vast majority of political generals were terrible, especially those who were immediately given large independent commands. That said, people like Richard Taylor and John C. Breckenridge started out in subordinate roles and gradually became quite competent - and neither man had any prior combat experience.
Any thoughts on where a General Lincoln might fall on the spectrum?