To behave ethically on the battlefield we first must

The correct answer to this open question is the following.

To behave ethically on the battlefield we first must establish the moral and ethical standards for warfare.

If you have access to any military manual on war, such as the Marine Corps, for instance, you will realize that even in war there are codes that must be followed. These codes and personal values will dictate the way soldiers are going to behave in the case the is no leader that gives the orders or the way to proceed in certain situations.