If you have the time and patience to do some very interesting reading, this post is for you.
I don't have a position on Grant's drinking, it's not something that interests me. However, I want to use a couple of terrific drinking pages on a Grant website to make a point about historians who cannot argue their points convincingly.
So we are looking at evidence regarding Grant and drink, and we're looking at historians addressing the topic, but we're not reaching conclusions of our own. Watching, thinking, not judging the evidence, but its treatment.
This is a long page; please have at it. Read it all. When done, ask yourself these questions: (1) Can a conclusion be reached about Grant's drinking? (2) If so, would it be firm or tentative? (3) How could you state such a conclusion with justice to all you have read?
Then read this long page of historians' comments.
I separated the sheep from the goats. You can too.