He introduces nominal asset markets in an infinite horizon version of the Barro-Gordon model. The author then analyzes the subset of sustainable policies compatible with any given asset price system at date t = 0. While there are usually many sustainable inflation paths associated with a given set of asset prices, the best sustainable inflation path is implemented if and only if the short-term nominal bond is priced at a certain discount rate. His results suggest that policy frameworks must also be evaluated on their ability to coordinate expectations.