  PKS 0438$-$436 at a redshift of $z=2.856$ has been previously recognized as
possessing perhaps the most luminous known synchrotron jet. Little is known
about this source since the maximum elevation above the horizon is low for the
Very Large Array (VLA). We present the first VLA radio image that detects the
radio lobes. We use both the 151 MHz luminosity, as a surrogate for the
isotropic radio lobe luminosity, and the lobe flux density from the radio image
to estimate a long term, time averaged, jet power, $\overline{Q} =1.5\pm 0.7
\times 10^{47} \rm{ergs~s^{-1}}$. We analyze two deep optical spectra with
strong broad emission lines and estimate the thermal bolometric luminosity of
the accretion flow, $L_{\rm{bol}} = 6.7 \pm 3.0 \times 10^{46}
\rm{ergs~s^{-1}}$. The ratio, $\overline{Q}/L_{\rm{bol}} = 3.3 \pm 2.6 $, is at
the limit of this empirical metric of jet dominance seen in radio loud quasars
and this is the most luminous accretion flow to have this limiting behavior.
Despite being a very luminous blazar, it previously had no $\gamma$-ray
detections (EGRET, AGILE or FERMI) until December 11 - 13 2016 (54 hours) when
FERMI detected a flare that we analyze here. The isotropic apparent luminosity
from 100 MeV - 100 GeV rivals the most luminous detected blazar flares
(averaged over 18 hours), $\sim 5-6 \times 10^{49} \rm{ergs~s^{-1}}$. The
$\gamma$-ray luminosity varies over time by two orders of magnitude,
highlighting the extreme role of Doppler abberation and geometric alignment in
producing the inverse Compton emission.
