"Recent military base closures and realignments in the United States have opened dozens of former training and testing sites to new uses and priorities. One common transition is to designate these lands as national wildlife refuges. This presents conservation opportunities on hundreds of thousands of hectares previously under military control, but the ecological restoration and subsequent reuse of these lands is complex and fraught with challenges. Unexploded ordnance, soil and water contamination, reinforced structures, and other military remainders exist on many of these sites, and wildlife refuge managers typically receive little funding or training to contend with such relicts. This paper acknowledges some of the real conservation opportunities provided by military-to-wildlife (M2W) refuges, but emphasizes that restoration and conservation measures at these sites remain bounded by physical and sociopolitical constraints. One outcome of these constraints is 'opportunistic conservation', where habitat and wildlife goals are shaped or constrained by the lingering presence of prior military uses. Working from case studies and interviews conducted at M2W sites in the United States, this research suggests that opportunistic conservation represents a limited vision for restoration and conservation at these places that also potentially obscures these limitations. At many of these same sites, however, more affirmative opportunistic conservation efforts exhibit creative responses given the conditions that exist."