What is the test for a de novo decision to grant or deny a petition for habeas corpus?

We review de novo a district court's decision to grant or to deny a petition for habeas corpus. Calderon v. Prunty, 59 F.3d 1005, 1008 (9th Cir.1995). We may affirm on any ground supported by the record even if it differs from the rationale of the district court. Bonin v. Calderon, 59 F.3d 815, 823 (9th Cir.1995), cert. denied, --- U.S. ----, 116 S.Ct. 718, 133 L.Ed.2d 671, reh'g denied, --- U.S. ----, 116 S.Ct. 977, 133 L.Ed.2d 897 (1996).