this comes a day after trump's surprised most of the world by announcing a withdrawal from syria that mattis disagreed with. mattis attempted to urge the president to go back on that withdrawal. the president disagreed and said he wouldn't do it and then mattis submitted his resignation. obviously the reason that mattis thinks it's a bad idea to withdraw from syria at the moment is because it gives more power to russia and iran to shape the future of the country. the pentagon and the state department and the intelligence community have said the fight against isis isn't over even though the physical -- of the extremist group has been rolled back. they worry if the u.s. precipitously pull us out of syria, it sends a message to allies we're not with you and we're not coordinated with you, it would also result in the resurgence of isis. >> joining me is barry mccaffrey. what do you think of this letter? do we have general?