Two recent theoretical models for the joint probability density function of wave slope and wave height are applied to the problem of using measured electromagnetic radiation of near-vertical incidence backscattered from the ocean's surface to determine the mean sea level. For each of the models, expressions for the electromagnetic bias (the difference between the mean of the electromagnetic response distribution and that of the true mean sea level) and the conditional backscatter cross sections, as functions of significant wave slope and specular incidence angle, are derived. The predictions from both models are qualitatively the same as those observed during the off-nadir airborne laser experiments of Hoge et al. (1984): a positive electromagnetic bias and greater backscatter cross section from regions above mean sea level under low-wind conditions and a negative electromagnetic bias and greater backscatter cross section from regions below mean sea level under moderate-wind conditions. More quantitative comparison appear limited by the ability to measure the mean square wave slope and determine the spectral nature of the sea.