On Morning Joe, Mike Barnicle and The Washington Post’s Eugene Robinson react to Sen. Bob Corker (R-TN), Chairman of the United States Senate Committee on Foreign Relations, and his public letter to President Barack Obama criticizing the negotiations with Iran in recent weeks. “The United States might well walk away from the deal with Iran. It’s not set in stone. Secretary John Kerry is going back to resume final negotiations next week and it’s not out of the realm of possibility that when push comes to shove they’ll say ‘no, we can’t do the deal,’” says Mike. Listen in on the conversation here. On MSNBC.