We have measured the parity-violating electroweak asymmetry in the elastic
scattering of polarized electrons from the proton. The kinematic point [[th
eta(1ab)] = 12.3 degrees and [Q(2)] = 0.48 (GeV/c)(2)] is chosen to provide
sensitivity, at a level that is of theoretical interest, to the strange el
ectric form factor G(E)(s). The result, A = -14.5 +/- 2.2 ppm, is consisten
t with the electroweak standard model and no additional contributions from
strange quarks. In particular, the measurement implies G(E)(s) + 0.39G(M)(s
) = 0.023 +/- 0.034(stat) +/- 0.022(syst) +/- 0.026(delta G(E)(n)), where t
he last uncertainty arises from the estimated uncertainty in the neutron el
ectric form factor. [S0031-9007(98)08312-4].