  Consideration is being given to upgrading the SuperKEKB e$^+$e$^-$ collider
with polarized electron beams, which would open a new program of precision
electroweak physics at a centre-of-mass energy of 10.58GeV, the mass of the
$\Upsilon(4S)$. These measurements include $\sin^2\theta_W$ obtained via
left-right asymmetry measurements of e$^+$e$^-$ transitions to pairs of
electrons, muons, taus, charm and b-quarks. The precision obtainable at
SuperKEKB will match that of the LEP/SLC world average and will thereby probe
the neutral current couplings with unprecedented precision at a new energy
scale sensitive to the running of the couplings. At SuperKEKB the measurements
of the individual neutral current vector coupling constants to b-quarks and
c-quarks and muons in particular will be substantially more precise than
current world averages and the current 3$\sigma$ discrepancy between the SLC
A$_{LR}$ measurements and LEP A$_{FB}^b$ measurements of $\sin^2\theta_W^{eff}$
will be addressed. This paper will include a discussion of the necessary
upgrades to SuperKEKB. This program opens an exciting new window in searches
for physics beyond the Standard Model.
