Yes, "Palestine" Consists of Both Banks of the Jordan

Pro-"Palestinians" while denying Jews any national identity with the Land of Israel mostly attempt to limit "Palestine" as a geo-political entity to the territory west of the Jordan River, even claiming "Palestine" existed during the period of Jesus (so as to enlist Christianity on their side).  But the Land of Israel, the Holy Land always extended to both sides of the Jordan River.

Consider this, though:

Salome danced at Machaerus. And John the Baptist was beheaded there. 

 

 

...Machaerus is one of the fortified royal palaces most often associated with Herod the Great, although they are actually of Hasmonean origin (except for Herodium, which was built and named by Herod)...Machaerus was thus the first to face an enemy from the east and could warn the others of the danger. According to Pliny the Elder, Machaerus was the strongest citadel in Judea after Jerusalem.

 

...Although Josephus described Machaerus in some detail, its location was forgotten even in ancient times....German explorer Ulrich Seetzen rediscovered the citadel at Machaerus only in 1807, and its lower city was first identified by the French Dominican Father Felix-Marie Abel of the École Biblique in 1909. In 1968 an exploratory trial excavation was conducted by Jerry Vardaman...

 
It was east of the Jordan River.  But still in the borders of Eretz-Ysrael.

^