The character of the rotational motion implied by the highly successful adiabatic rotational model is examined with the objective of determining the ground rules for a microscopic rotational theory based on this model. It is deduced that the adiabatic model implies rotational flow, i.e. rigid-body flow except that the particles are not frozen in position. However, the rotational flow of the adiabatic model does not exclude the possible existence in the nucleus of rotationally invariant clusters. As a particular example of such clustering, we propose a twofluid model of nuclear rotations to describe the possibility of a centrally located rotationally invariant superfluid core. It is shown that the inertia tensor for rotational flow is the rigid-body tensor. But it is also shown that clusters would participate in the rotational flow as if they were elementary particles with their masses concentrated at their centers of mass and would thereby effect a reduction of the moments of inertia. Thus the fact that observed moments of inertia, for nuclei described by the adiabatic rotational model, are considerably smaller than the rigidbody moments evaluated for the nucleon mass distribution can be attributed to the presence of cluster correlations. The Inglis cranking model is examined in the light of this interpretation.