  While it is often stated that the notion of electroweak (EW) naturalness in
supersymmetric models is subjective, fuzzy and model-dependent, here we argue
the contrary: electroweak naturalness can be elevated to a {\it principle}
which is both objective and predictive. We demonstrate visually when too much
fine-tuning sets in at the electroweak scale which corresponds numerically to
the measure \Delta_{BG}~\Delta_{EW}> 30. While many constrained SUSY models are
already excluded by this value, we derive updated upper bounds on sparticle
masses within the two-extra parameter non-universal Higgs model (NUHM2). We
confirm the classic Barbieri-Giudice (BG) result that \Delta_{BG}<30 implies mu
<350 GeV. However, by combining dependent soft terms which appear as multiples
of m_{3/2} in supergravity models, then we obtain m(gluino)< 4 TeV as opposed
to the BG result that m(gluino)<350 GeV. We compare the NUHM2 results to a
similar scan in the pMSSM with 19 weak scale parameters. In the pMSSM with
complete one-loop scalar potential plus dominant two-loop terms, then a
m(gluino)<7 TeV bound is found. Our tabulation of upper bounds provides a
target for experimenters seeking to discover or else falsify the existence of
weak scale supersymmetry. In an Appendix, we show contributions to the
naturalness measure from one-loop contributions to the weak scale scalar
potential.
