  The electroweak phase transition broke the electroweak symmetry. Perturbative
methods used to calculate observables related to this phase transition suffer
from severe problems such as gauge dependence, infrared divergences, and a
breakdown of perturbation theory. In this paper we develop robust perturbative
tools for dealing with phase transitions. We argue that gauge and infrared
problems are absent in a consistent power-counting. We calculate the finite
temperature effective potential to two loops for general gauge-fixing
parameters in a generic model. We demonstrate gauge invariance, and perform
numerical calculations for the Standard Model in Fermi gauge.
