DY,
“If the Rebbe was a navi (he wasn’t), then according to the basic gemara and rishonim, he was a navi sheker.”
Interesting, I think the ones THINKING he is a Navi have more in common with Navuah then the Rebbe Himself!
? הא כיצד
Very simple:
מיום שחרב בית המקדש ניטלה נבואה מן הנביאים וניתנה לשוטים ולתינוקות