The Pope Did It?

[SSlater]

I can see that I have a great deal of reading to do. I never paid much attention to Chiniquy, since he was a former priest, and thus, I never expected him to say anything nice about the church. Then I read authors that I trust and read - they never have anything to say about him, I classified him as a "Crank".
What "assassination plot" could he have warned Lincoln about, in 1861? (Lincoln was said to have a whole file of Plots, should I just pick one?). Why did the Church defrock him? I need more information before I waste my time on a "Crank".
I'm not saying He's wrong, or that I am right, I just don't know.