Seldom has a phrase risen so quickly to such infamy as the expression, “From the river to the sea.” Often paired with “Palestine will be free,” the expression is often heard at pro-Palestinian protests. University campuses are in an uproar over it. Left-wing politicians in Britain and the U.S. have been censured or even suspended by their parties for daring to use it. It is widely held to be an antisemitic call for the destruction of Israel. The fact that it was used in PLO statements in the 1960s, when that organization was officially committed to the destruction of Israel, and more recently in the Hamas charter, lends serious credence to these concerns.
It has been in use for years I doubt that any attempt to criminalize it will succeed.
