  Spin ice is a frustrated magnetic system that at low temperatures exhibits a
Coulomb phase, a classical spin liquid with topological order and deconfined
excitations. This work establishes the presence of a Coulomb phase with
coexisting ferromagnetic order in a microscopic model of classical spin ice
subject to uniaxial lattice distortion. General theoretical arguments are
presented for the presence of such a phase, and its existence is confirmed
using Monte Carlo results. This example is used to illustrate generic
properties of spin liquids with magnetic order, including deconfinement of
monopoles, signatures in the neutron-scattering structure factor, and critical
behavior at phase transitions. An analogous phase, a superfluid with
spontaneously broken particle-hole symmetry, is demonstrated in a model of
hard-core lattice bosons, related to spin ice through the quantum-classical
correspondence.
