  Local gauge symmetries reduce to the identity on the observables, as well as
on the physical states (apart from reflexes of the local gauge group topology)
and therefore their use in Quantum Field Theory (QFT) asks for a justification
of their strategic role. They play an intermediate role in deriving the
validity of Local Gauss Laws on the physical states (for the currents which
generate the related global gauge group); conversely, we show that local gauge
symmetries arise whenever a vacuum representation of a local field algebra
${\cal{F}}$ is used for the description/construction of physical states
satisfying Local Gauss Laws, just as global compact gauge groups arise for the
description of localizable states labeled by superselected quantum numbers. The
above relation suggests that the Gauss operator, which by locality cannot
vanish in ${\cal{F}}$, provides an intrinsic characterization of the
realizations of a gauge QFT in terms of a local field algebra and of the
related local gauge symmetries.
