Right you are in saying "The claimed right of Palestinians to return to Israel will be an impossible obstacle", seeing that they were not pushed out by the Jewish Army in 1948 but told by their own Arab Leaders to flee. A statement made by Syria's Prime Minister after the 1948 War proves this as follows : "Since 1948 it is WE who demanded the Return of the Refugees - while it is WE WHO MADE THEM LEAVE - WE wrought disaster upon Arab Refugees by inviting them and bringing pressure upon them TO LEAVE" speech by Khaled Al-Azmi Syria's Prime Minister after the 1948 War. The fact that the Palestinian/ARABS as they were known then fled of their very own will, makes it a problem for them.
Mexico approves U.S. extradition warrant for fugitive kingpin 'El Chapo' (Reuters)
from the article: Persuade the people