  We study the elastic scattering of polarized protons from He isotopes. The
central and spin-orbit parts of the optical potential are derived using the
Glauber theory that can naturally take account of the breakup effect of the He
isotopes. Both the differential cross section and the vector analyzing power
for $p+^{4,6,8}$He scattering at 71 MeV are in reasonable agreement with
experiment. Scattering observables at 300 MeV are predicted. The Pauli blocking
effect is examined at 71 MeV.
