  The relativistic heavy ion collider (RHIC) was constructed to achieve an
asymptotic state of nuclear matter in heavy ion collisions, a near-ideal gas of
deconfined quarks and gluons denoted quark-gluon plasma or QGP. RHIC collisions
are indeed very different from the hadronic processes observed at the Bevalac
and AGS, but high-energy elementary-collision mechanisms are also non-hadronic.
The two-component model (TCM) combines measured properties of elementary
collisions with the Glauber eikonal model to provide an alternative asymptotic
limit for A-A collisions. RHIC data have been interpreted to indicate formation
of a {\em strongly-coupled} QGP or "perfect liquid". In this review I consider
the experimental evidence that seems to support such conclusions and
alternative evidence that may conflict with those conclusions and suggest
different interpretations.
