  The superfluid density is calculated theoretically for incompressible vortex
lattices in two dimensions that have isolated dislocations quenched in by a
random arrangement of pinned vortices. The latter are assumed to be sparse and
to be fixed to material defects. It is shown that the pinned vortices act to
confine a single dislocation of the vortex lattice along its glide plane.
Plastic creep of the two-dimensional vortex lattice is thereby impeded, and
macroscopic phase coherence results at low temperature in the limit of a dilute
concentration of quenched-in dislocations.
