The requirements of the Endangered Species Act (ESA) and greater emphasis on ecosystem management of natural resources on federal lands has presented some difficult challenges to the Department of Defense (DOD). Unlike most other agencies managing federal lands, DOD's national security mission requires the extensive use of its lands to conduct realistic training and the testing of military weapons and equipment. This article examines the Army's experience in attempting to reconcile these requirements involving the proposed reintroduction of the endangered Mexican gray wolf on the White Sands Missile Range. The Army's initial opposition to the proposed reintroduction of the Mexican gray wolf resulted in prolonged litigation that actually reduced the Armys ability to influence the outcome. Drawing on this experience and the experiences at other installations like Fort Bragg, North Carolina, the Army has issued new guidance directing base commanders to actively seek to incorporate conservation into their missions to ensure that environmental programs involving Army land are entered into as a matter of mutual consent, rather than through the imposition by judicial decree.