Do you think there are many Marines who don't realize how this case has affected the ROE's currently being used in Iraq? Do you think there are many Marines who respect Murtha and don't realize his political impact on having these charges filed? And I don't mean just active duty types; even those stationed back at Camp Pendleton get the stories.
The actual facts relevant to the case are the top layer of defense, but these "ideologies" form the background that a panel of peers will be using in their judgement.
What should a defense lawyer base the case on?
Appealing to those ideologies is grounds for an instant mistrial. The message a verdict may send is not an appropriate consideration.