  Gauge coupling unification and the stability of the Higgs vacuum are among
two of the cherished features of low-energy supersymmetric models. Putting
aside questions of naturalness, supersymmetry might only be realised in nature
at very high energy scales. If this is the case, the preservation of gauge
coupling unification and the stability of the Higgs vacuum would certainly
require new physics, but it need not necessarily be at weak scale energies. New
physics near the unification scale could in principle ensure Grand Unification,
while new physics below $\mu \sim 10^{10}$ GeV could ensure the stability of
the Higgs vacuum. Surprisingly however, we find that in the context of a
supersymmetric SO(10) Grand Unified Theory, gauge coupling unification and the
Higgs vacuum stability, when taken in conjunction with existing
phenomenological constraints, require the presence of $\mathcal{O}$(TeV)-scale
physics. This weak-scale physics takes the form of a complex scalar SU(2)$_L$
triplet with zero hypercharge, originating from the $\mathbf{210}$ of SO(10).
