SWEM Allocation Model is a mathematical optimization model which allocates strategic weapons in a two-sided nuclear exchange and provides damage results and specific allocations. The model is useful in defining levels of parity between the nuclear arsenals of two nations. Version 2 of the model expands the allocation matrix to include attack on defense installations and provides the optimal tradeoff between attack of defense installations, weapon targets silos and cities. The document describes a mathematical optimization model which provides allocations and damage levels in a two-strike nuclear war. It is an extension of an allocation model Strategic Weapons Exchange Allocation Model-Version I which has been documented in manuals mentioned in the Introduction. The new allocation model allows attack on defense installations as well as cities and weapon targets, and provides optimal trade-offs in allocation between defense installations, cities, and weapon targets. The document describes the capabilities and limitations of the model, gives the format of the input and output of the model, provides example problems and contains the annotated FORTRAN listing of the program.