  The Galactic center black hole candidate Sgr A* is the best target for
studies of low-luminosity accretion physics, including with near-infrared and
submillimeter wavelength long baseline interferometry experiments. Here we
compare images and spectra generated from a parameter survey of general
relativistic MHD simulations to a set of radio to near-infrared observations of
Sgr A*. Our models span the limits of weak and strong magnetization and use a
range of sub-grid prescriptions for electron heating. We find two classes of
scenarios can explain the broad shape of the submillimeter spectral peak and
the highly variable near-infrared flaring emission. Weakly magnetized
"disk-jet" models where most of the emission is produced near the jet wall,
consistent with past work, as well as strongly magnetized (magnetically
arrested disk) models where hot electrons are present everywhere. Disk-jet
models are strongly depolarized at submillimeter wavelengths as a result of
strong Faraday rotation, inconsistent with observations of Sgr A*. We instead
favor the strongly magnetized models, which provide a good description of the
median and highly variable linear polarization signal. The same models can also
explain the observed mean Faraday rotation measure and potentially the
polarization signals seen recently in Sgr A* near-infrared flares.
