  We examine the possibility of measuring the three gauge couplings at high
scales at the LHC, in order to see the first steps as they run toward Grand
Unification at much higher energies. Using the MSSM with sparticle masses of
several hundred GeV as an example of a theory in which the couplings do unify
at very high energies, we find that the processes pp->lv, pp->l+l- and
pp->gamma+j can be useful to discriminate the SM from the MSSM with masses at
the few hundred GeV scale, and determine that the couplings are converging at
better than the SM prediction toward the GUT scale. Such measurements
indirectly probe the existence of lower mass states, charged under the SM gauge
groups, but which may be difficult to produce directly or extract from
backgrounds at the LHC.
