When an elected official calls on his private line asking for a public favor then there is no inherit right to privacy over that conversation or of the telephone number used - that number is not a private number any longer.
PS: If graham changes the number he is a wussy who can't fight back. If he was smart he would answer every call but he is not smart he is a political hack who is working for neocon filth who want the USA to re-wage war in the Middle East.