How to prepare for a plagiarism hearing?

The size of the ignment doesn't really matter. The point is that you stole someone else's words and ideas. (To shrug the igment off as "quite minor" is like saying a murder doesn't matter because the victim was a nobody.) Academics is all about words and ideas, so to p off someone else's thoughts as your own is a serious offense (and reason for expulsion at some schools). You apparently didn't take the ignment seriously enough so you took a shortcut -- and you got caught. Professors often use scanning software that looks for identical phrasing. If they find enough matches, they can make a pretty strong case that you have plagiarized someone else's work. I suppose you could argue that you forgot to cite the online essay, but another student's essay is not a strong source for a history major anyway. You may just be screwed on this because if you're found guilty of plagiarism, you'll have a tough time getting accepted into law school.