  SGR 0418+5729 is a "Rosetta Stone" for deciphering the energy source of Soft
Gamma Ray Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs). We show a model
based on canonical physics and astrophysics for SGRs and AXPs powered by
massive highly magnetized rotating white dwarfs (WDs), in total analogy with
pulsars powered by rotating neutron stars (NSs). We predict for SGR 0418+5729 a
lower limit for its spin-down rate, $\dot{P} \geq L_X P^3/(4\pi^2 I)=1.18\times
10^{-16}$ where $I$ is the moment of inertia of the WD. We show for SGRs and
AXPs that, the occurrence of the glitch and the gain of rotational energy, is
due to the release of gravitational energy associated to the contraction and
decrease of the moment of inertia of the WDs. The steady emission and the
outburst following the glitch are explained by the loss of rotational energy of
the Wds, in view of the much larger moment of inertia of the WDs, as compared
to the one of NSs and/or quark stars. There is no need here to invoke the
unorthodox concept of magnetic energy release due to decay of overcritical
magnetic fields, as assumed in the magnetar model. A new astrophysical scenario
for the SGRs and AXPs associated to Supernova remnants is presented. The
observational campaigns of the X-ray Japanese satellite Suzaku on AE Aquarii
and the corresponding theoretical works by Japanese groups and recent results
of the Hubble Space Telescope, give crucial information for our theoretical
model. Follow-on missions of Hubble Telescope and VLT are highly recommended to
give further observational evidence of this most fundamental issue of
relativistic astrophysics: the identification of the true SGRs/AXPs energy
source.
