  We show that suppression of vortices in the Ashkin Teller ferromagnet on a
square lattice splits the order-disorder transition and opens up an
intermediate phase where the macroscopic symmetry enhances to U(1). When we
selectively suppress the formation of non-chiral vortices, chiral vortices
proliferate and replace the U(1) phase with a new phase where chiral symmetry
is restored. This result demonstrates a fascinating phenomenon in which the
symmetry information encoded in topological defects manifests itself in the
symmetry of the phase where the defects proliferate. We also show that this
phenomenon can occur in all $\mathbb{Z}_n$ ferromagnets with even values of
$n$.
