  In the unified schemes for extragalactic radio sources, the quasars and BL
Lac objects are intrinsically similar to the Fanaroff-Riley class II and I
radio galaxies respectively, but appear to be different because they are viewed
at different angles to the line-of-sight. The quasars and BL Lac objects are
observed at small viewing angles while the radio galaxies lie close to the
plane of the sky. In such schemes, the quasar or BL Lac nucleus is hidden from
our view by a putative torus when the source is inclined at a large angle to
the line-of-sight and appears as a radio galaxy. Such a scenario should also
affect the observed polarization properties of the cores, with the cores in the
radio galaxies and weak-cored quasars being less polarized than the
core-dominated quasars and BL Lacs due to Faraday depolarization by the
magnetoionic medium in the obscuring torus or disk. In this paper, we report
that the core polarization of radio galaxies and weak-cored quasars is indeed
much smaller than for the core-dominated quasars and BL Lacs. We suggest that
this is due to the depolarization caused by the obscuring torus or disk,
providing further evidence in favour of the unified schemes.
