  The LHC is exploring electroweak (EW) physics at the scale EW symmetry is
broken. As the LHC and new high energy colliders push our understanding of the
Standard Model to ever-higher energies, it will be possible to probe not only
the breaking of but also the restoration of EW symmetry. We propose to observe
EW restoration in double EW boson production via the convergence of the
Goldstone boson equivalence theorem. This convergence is most easily measured
in the vector boson plus Higgs production, $Vh$, which is dominated by the
longitudinal polarizations. We define EW restoration by carefully taking the
limit of zero Higgs vacuum expectation value (vev). EW restoration is then
measured through the ratio of the $p_T^h$ distributions between $Vh$ production
in the Standard Model and Goldstone boson plus Higgs production in the zero vev
theory, where $p_T^h$ is the Higgs transverse momentum. As EW symmetry is
restored, this ratio converges to one at high energy. We present a method to
extract this ratio from collider data. With a full signal and background
analysis, we demonstrate that the 14 TeV HL-LHC can confirm that this ratio
converges to one to 40% precision while at the 27 TeV HE-LHC the precision will
be 6%. We also investigate statistical tests to quantify the convergence at
high energies. Our analysis provides a roadmap for how to stress test the
Goldstone boson equivalence theorem and our understanding of spontaneously
broken symmetries, in addition to confirming the restoration of EW symmetry.
