  We present here the first results from the Chandra ERA (Environments of
Radio-loud AGN) Large Project, characterizing the cluster environments of a
sample of 26 radio-loud AGN at z ~ 0.5 that covers three decades of radio
luminosity. This is the first systematic X-ray environmental study at a single
epoch, and has allowed us to examine the relationship between radio luminosity
and cluster environment without the problems of Malmquist bias. We have found a
weak correlation between radio luminosity and host cluster X-ray luminosity, as
well as tentative evidence that this correlation is driven by the subpopulation
of low-excitation radio galaxies, with high-excitation radio galaxies showing
no significant correlation. The considerable scatter in the environments may be
indicative of complex relationships not currently included in feedback models.
