Article dans une revue: In a forward-looking business cycle model, central banks can achieve the (timeless)optimal commitment equilibrium even in the absence of a commitment technology, if they are delegated with an objective function that is different from the societal one. The paper develops a general linear-quadratic method to solve for the optimal delegation parameters that generate the optimal amount of inertia in a Markov-perfect equilibrium, and studies the optimal design of some policy regimes that are nested within this framework: the (squared) optimal targeting rule; inflation, output-gap growth and nominal income growth targeting; and inflation and output-gap contracts.