Comment on "Effects of spatial dispersion on electromagnetic surface modes and on modes associated with a gap between two half spaces"

Recently Bo E. Sernelius [Phys. Rev. B {\bf 71}, 235114 (2005)] investigated the effects of spatial dispersion on the thermal Casimir force between two metal half spaces. He claims that incorporating spatial dispersion results in a negligible contribution from the transverse electric mode at zero frequency as compared to the transverse magnetic mode. We demonstrate that this conclusion is not reliable because, when applied to the Casimir effect, the approximate description of spatial dispersion used is unjustified.