Reply To: Who is the new leader of Klal Yisrael?

You will not find the phrase “posek hador” used anywhere in any meaningful way. The Tzitz Eliezer uses it all over the place in his titles, and either the Teshuvos Maharshal writes it among the titles to the Ramah, or the Teshuvos Ramah about the Maharshal. I forget. But in any case, the title connotes no halachic status.