The method of localized charge distributions, originally implemented for semiempirical molecular orbital (MO) theory, is reintroduced and implemented for ab initio self-consistent field MO theory. This theory is then used in conjunction with localized second-order Moller-Plesset (MP2) pair energies to analyze the hydrogen bond in the water dimer. It is found that this hydrogen bond can be explained as the competition between the intrawater electronic kinetic energy pressure and the interwater potential energy suction.