This paper examines a voter model for the US which is interconnected with the partisan theory. In our model, voters are rational and forward-looking. They are perfectly informed about the preferences of political parties and about the state of the economy. The predictions of our voter model differ from the predictions of conventional voter models, according to which the incumbent benefits from low unemployment and low inflation, irrespective of its political colour. In a partisan setting, the democratic party benefits from high unemployment and the republican party benefits from high inflation. Regressions of presidential approval rates indicate that the predictions of both the partisan voter model and the conventional model are consistent with the data.