How the hell is he still claiming Democrats have Key 2? In the book, he clearly states the winner must have 2/3's of the delegates...HRC got 3/5's of the delegates. 3/5's is less than 2/3's. This is not rocket science.
He believes that since Clinton was never in serious danger of losing her lead after SC, and because Bernie was supportive at the convention, it doesn't count as a "serious" challenge.
Back in March, he was saying just the opposite. He had Key 2 as a 'False'. (Don't have the link to hand). Lichtman has been all over the place this year, and using "oh, but Trump is different" as an excuse is just a bit feeble.
To be fair on Lichtman, citing him as a "never wrong" pundit is the media's spin on his predictions. He
was 'wrong' in 2000 - people don't want to know who's going to win the popular vote, they want to know who their president is going to be for the next four years. A prediction that tells them anything else is just not as valuable.