President can sign anything. No intl agreement is binding without Senate ratification.
Yes! A lot of this is Israeli political grand-standing. Netanyahu is in the US to speak to his political base in Israel. There is an election in less than two weeks.
Netanyahu is up to his ass in corruption charges (some quite serious, ie the submarine kickback stuff). He's pulling all the stops. Syria strikes, Gaza incursion, Golan Heights Annex, Jerusalem Embassy.
He is saying: 'Look! 'I, and I alone, have the contacts in Washington. Benny Gantz is a loser! I sleep in Jared Kushner's bed! Vote for ME!'