  Screening of an external random potential by a two dimensional (2D) Fermi
liquid may be strongly dependent on the degree of its polarization. This is
considered as a possible mechanism for the observed strong magnetoresistance of
the 2D electron liquid in the magnetic field parallel to the electron plane. A
Hartree-Fock calculation for the weakly disordered Hubbard model which
qualitatively describes the experiments on the diagonal and the Hall
resisitivity in the finite-temperature metallic state in the high mobility Si
inversion layers is presented.
