Do you mean by legality the fact that arab palestinians had no legal claim to the territory initially as the territory was never theirs to begin Do you mean by legal the fact that waves of arab palestinian immigrants to the region had no more claim to the region (and historically much less) than the jewish waves of immigrants at predominantly the end of the 18th and the beginning of the 19th centuries? Do you mean by legal the fact that rather than choosing a state for themselves (on many occasions but esp 1947), arab pals often elected to choose to embrace the goals of their arab brethren to wipe israel off the map or in the very least get out of the way to allow it to happen? Do you mean by legal the standard by which virtually any other country in the world has grown, EXCEPT not with manifest destiny, or conquest, but instead as a consequence of multiple wars brought about by those intent upon destroying israel....and then losing that fight? Do you mean by legal a continuous active presence in the region in both large number and small numbers from a time centuries before islam all the way through the rise and fall of the islamic empire, to present day and time. ?
U.S. Defense Secretary Carter: Russia escalating Syria war by targeting moderates (Reuters)