  We use the framework of Glauber extended Soft-Collinear Effective Theory to
explicitly derive a gauge invariant expression of the jet quenching parameter
$\hat{q}$. The effective theory approach offers a systematic power counting
scheme at the Lagrangian level and allows for a consistent treatment of the
relevant scales in the problem. Employing this approach in a covariant gauge
scenario lead to an expression for $\hat{q}$ containing the expectation value
of two light-cone Wilson lines. We find that in a general gauge, additional
interaction terms in the Lagrangian have to be considered, leading to the
introduction of transverse gauge links.
