  In the limit of a high temperature T and a large quark-mass M, implying a
small gauge coupling g, the heavy quark contribution to the spectral function
of the electromagnetic current can be computed systematically in the
weak-coupling expansion. We argue that the scale hierarchy relevant for
addressing the disappearance ("melting") of the resonance peak from the
spectral function reads M >> T > g^2 M > gT >> g^4 M, and review how the heavy
scales can be integrated out one-by-one, to construct a set of effective field
theories describing the low-energy dynamics. The parametric behaviour of the
melting temperature in the weak-coupling limit is specified.
