If you decide to complete this mission later on the game, after Colonel Moore tells you to talk to Ranger Grant about protecting the President, Ranger Grant will just sit there and grin and you wont be able to talk to him.
Since this is an Achievement mission, its really annoying that is we cant complete because of a bug that should have not been in the game, or should have been fixed long ago.
Please take care of this. Thank you. I am a big fan, but this game is BUGGY!