How large is the total cross section at supercollider energies?

Although the value of the total cross section is critical for the operation and physics exploitation of supercolliders, we have until now been unable to anticipate its magnitude. Extrapolations of low-energy data patterned after models with a varying degree of dynamical justification, and invariably a too large number of free parameters to be truly predictive, led to a wide range of predictions. We point out that a series of new measurements at the Fermilab Tevatron Collider on forward-scattering parameters dramatically narrows the range of extrapolations and we anticipate that ${\sigma }_{\mathrm{tot}}=107\mathrm{}\pm 4 \mathrm{mb}$ at $\sqrt{s}=16\mathrm{}$ TeV, and ${\sigma }_{\mathrm{tot}}=121\mathrm{}\pm 5 \mathrm{mb}$ at $\sqrt{s}=40\mathrm{}$ TeV, using a QCD-inspired parametrization. More surprisingly, the model dependence of the extrapolations is reduced by the new data to the point that a wide range of models investigated converge on the above values.