If he were unjustly accused then why were his lawyers all for taking the proposal that Chief Justice Chase held out regarding the 14th Amendment? They apparently were not as sure of an innocent verdict as you, or so hell-bent on martyrdom as Jefferson Davis.
'In the autumn of 1867 Mr. O'Conor, after incessant efforts, aided by men of all parties succeeded in getting a time appointed for the decision of Mr. Davis's case, either for trial or a nolle prosequi, but both would have preferred the former as a test question. As winter drew on Mr. Davis was summoned to Richmond, but the nolle prosequi was filed.'
From Bouvier Law Dictionary Rev. 6th ed. (1856), NOLLE PROSEQUI, practice. An entry made on the record, by which the prosecutor or plaintiff declares that he will proceed no further.
The federal government abandoned the case, not Davis. Specifically, due to the complete pardon by Johnson 25 Dec 1868. A pardon that Jefferson Davis did not want.
'If my opinion is worth anything, you can ALWAYS say that few people could have done better than Mr. Davis. I knew of none that could have done as well.' - R. E. Lee
I continue to be certain that there is no such thing an "innocent verdict."