Virtual water - embedded in an agricultural commodity by virtue of evapotranspiration during crop growth - is effectively consumed by the purchaser. In water-poor economies, it breaks their dependence on local water-for-food and acts as a political stabilizer. Tony Allan's concept remains highly relevant in the irrigated drylands for which it was developed, but calculating water footprints for agriculture elsewhere should take account of the non-agricultural counterfactual - which may consume more water than the agriculture that replaces it. Otherwise, use of water footprinting, for example, in trade policy, will be misleading and counterproductive.