  We present and discuss the radio observations of 27 Type Ia supernovae (SNe
Ia) observed over two decades with the Very Large Array. No SN Ia has been
detected so far in the radio, implying a very low density for any possible
circumstellar material established by the progenitor, or progenitor system,
before explosion. We derive 2-sigma upper limits to a steady mass-loss rate for
individual SN systems as low as ~3 X 10^{-8} Msun yr^{-1}, discriminating
strongly against white dwarf accretion via a stellar wind from a massive binary
companion in the symbiotic star, an example of the ``single degenerate''
scenario. However, a white dwarf accreting from a relatively low mass companion
via a sufficiently high efficiency (>60-80%), Roche lobe overflow is still
consistent with our limits. The ``double degenerate'' merger scenario also
cannot be excluded.
