If I were an Atheist, I would carry around a piece of paper in my wallet that said this:

Ronald Reagan, in Sept 1980 said, with complete seriousness and sincerity, “I am God, you should worship me.”

Then the next time a Christian brings up the Jesus Trilemma (Lunatic, Liar, Lord), I would pull out that piece of paper and say “Given this – what do you believe about Ronald Reagan? Was he crazy, trying to fool us, or was he really God.”

And (eventually) the Christian would say “I don’t believe that piece of paper”.

And I would say “Aha!”*

C.S. Lewis was assuming the arguer believed the Bible. We would be wise to remember this.

* Note: I wouldn’t say “Exactly.” That would be smarmy, as I have previously noted.