LLL, is, of course, Liar, Lunatic, or Lord. It is based on C. S. Lewis's argument in Mere Christianity:
I am trying here to prevent anyone saying the really foolish thing that people often say about Him: I’m ready to accept Jesus as a great moral teacher, but I don’t accept his claim to be God. That is the one thing we must not say. A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic — on the level with the man who says he is a poached egg — or else he would be the Devil of Hell. You must make your choice. Either this man was, and is, the Son of God, or else a madman or something worse. You can shut him up for a fool, you can spit at him and kill him as a demon or you can fall at his feet and call him Lord and God, but let us not come with any patronizing nonsense about his being a great human teacher. He has not left that open to us. He did not intend to.
It is sometimes thought you can refute it just by adding a logically possible fourth option, such as Legend. However, in a Presidential election, adding a third party does not make it less likely that either the Republican or the Democratic candidate will win the election. The additional alternative has to be plausible, and Gilson here argues that the Legend option is not. This is his blog treatment of it.