  The 2+1 dimensional pure SU(N) gauge theories with N <= 4 are candidates for
applying the powerful tools of scaling and universality to their deconfinement
transitions at finite temperature. The corresponding 2 dimensional q-state
Potts models with q <= 4 have 2nd order transitions, and we can exploit many
exact results to obtain accurate critical couplings, transition temperatures,
critical exponents, and the leading behavior of the continuum string tension
near the phase transition on one side, together with its dual on the other.
Thereby, the self-duality of the 2d spin models is reflected in a duality
between spacelike vortices and confining electric fluxes. We also discuss the
relevance of center symmetry and the corresponding vortices for confinement in
full QCD when the electromagnetic interactions of fractionally charged quarks
are included.
