。
It isn't entirely clear which side wanted it.
Literal
Which [subj-が] wanted [nominalizer-のか] clearly-[topic-とは] not-do.
判然とはしない combines 判然と 'clearly / distinctly' with とはしない, giving 'does not become clearly (determined).' The scoping は inside とは contrasts — 'as for clearly, it is not (the case).' どちらが望んだのか is an embedded question acting as the subject clause of the larger predicate. 望む is a formal verb for 'to wish / want / desire,' weightier than 欲しい.