Snapedom

I can only guess that Albus' position on the Wizengamot either comes at a later date without the need for any form of prior law background (I don't think we actually know when he joined it, do we?) or there is some form of law that insists that once someone is found guilty, no one else can be tried for the same crime?

What we know about Albus' political status is that he had already been someone's candidate for Minister at least twice before 1945. We also know he tried to get Morfin's case reopened but Morfin died in the meanwhile. (Did Albus sigh in relief that he did not have to reveal just how much he knew about young Tom?)

I agree Albus didn't know that Tom had made a Horcrux until Godric's Hollow, and certainly since he did not expect multiple Horcruxes he did not know what to make of Tom's collection of historical artifacts. I'm not saying he should ahve been able to conclude that Tom had made a Horcrux (or 5) based on his changed looks, only that he supposedly realized Tom had been involved in serious Dark Magic. Wouldn't he want to know what that was, especially as Tom was leading a group of followers?