  The polarized synchrotron data of the northern C-BASS survey show a
surprisingly low linear polarization fraction, $\Pi\simeq 3\%$, while the
magnetic field polarization features coherent structures over rather large
angular scales. The low polarization degree points to a strong dominance of the
turbulent magnetic field -- in agreement with the observation that the total
synchrotron intensity is much larger than expected from the regular component
in current models for the Galactic magnetic field (GMF). In contrast, studies
of cosmic ray propagation employing these GMF models suggest that cosmic rays
propagate anisotropically, what in turn requires weak turbulent fields. As a
solution to this contradicting requirements, we suggest that the GMF consists
of three components with different levels of turbulence: a disk dominated by
the turbulent field, a halo dominated by the regular field, plus an extended
turbulent halo field.
