In Mary Ellen C. v. Arizona Department of Economic Security, 193 Ariz. 185, 191-92, P32, 971 P.2d 1046, 1052-53 (App. 1999), the Court observed regarding the constitutional protections implicated in seeking termination of parental rights that "the combined effect of the fundamental character of a parent's right to his child and the severity and permanence of termination dictates that the court sever the parent-child relationship only in the most extraordinary circumstances, when all other efforts to preserve the relationship have failed." Id. Thus, the Court held that severance based on mental illness, a subsection (B)(3) severance, could be upheld only if the Department also proved that the condition either was not amenable to rehabilitative efforts or that such efforts had been provided but had proven unsuccessful. Mary Ellen C., 193 Ariz. at 193, P42, 971 P.2d at 1054. But we also held that there is no constitutional mandate to undertake reunification efforts that are futile. Id. The Department is obligated to undertake reunification only in cases where there is a reasonable prospect of success. Id. at 192, P34, 971 P.2d at 1053.