The U.S. military must internalize international environmental principles into its military operations in foreign countries in order to fully win over the hearts and minds of the local population. Two principles in particular, the obligation to prevent transboundary environmental harm and the polluter pays principle have the potential to make lasting changes in the countries where contingency operations are conducted. This paper will examine the current U.S. military guidance, directives, and regulations concerning environmental harm during contingency operations. Next, the paper will examine the origins of each of the international environmental principles. Finally, the paper will use the contingency operations of Iraq and Afghanistan as a backdrop to stress the importance of internalizing these international environmental principles in future operations.