  With high-sensitivity kiloparsec-scale radio polarimetry, we can examine the
jet-medium interactions and get a better understanding of the blazar divide in
radio-loud (RL) AGN. We are analyzing the radio polarimetric observations with
the EVLA and GMRT of 24 quasars and BL Lacs belonging to the Palomar-Green (PG)
sample. The RL quasars show extensive polarisation structures in their cores,
jets, lobes, and hotspots, whereas preliminary results suggest that BL Lacs
exhibit polarisation primarily in their cores and inner jet regions. These
findings imply that both intrinsic (central engine-related) and extrinsic
(environment-related) variables are important in the formation of the blazar
subclasses. The Fanaroff-Riley (FR) dichotomy can also be studied assuming RL
unification and looking through the lens of blazars. Due to the radio-unbiased
nature of the optically/UV-selected PG sample, we find a large fraction of the
PG quasars are restarted, distorted (S- or X-shaped), or have a hybrid FR
morphology.
