On top of the barriers to district space already mentioned, there are others. Among them are intricacies of the bureaucratic processes involved, inadequacies in the condition or location of available facilities, stalemates regarding the terms of agreements between districts and schools, and lack of effective legal tools to enforce requirements.⁷⁵ In California, a serious obstacle is the lack of punitive measure in the law for districts that do not abide by required timelines—an issue that has been described as the "Achilles' heel of Proposition 39."⁷⁶ In Washington, D.C., one of the most common sticking points has been the definition of a vacant facility.⁷⁷ In some cases, DCPS's claims that space is needed for other purposes may be legitimate, and in other cases it is not clear. Such examples illustrate the implementation challenges related to district provision of facilities for charter schools.