If this is in fact the first time that America has given Israel such a stark ultimatum, it could end up being a significant game changer over the longer-term. Because this is the US at last openly saying that Israel is giving every indication of not being a credible partner seeking peace. This open admission may in turn help the Palestinians to get support from less expected areas if, as Assad says, they turn once again to the international sector for help.
U.S. State Dept. 'deeply concerned' about Israel's approval of new settlement construction (Reuters)