This paper investigates how institutional constraints discipline the behavior of discretionary governments subject to an expenditure bias. The focus is on constraints implemented in actual economies: monetary policy targets, limits on the deficit and debt ceilings. For a variety of aggregate shocks considered, the best policy is to impose a minimum primary surplus of about half a percent of output. Most welfare gains from constraining government behavior during normal times, which to a large extent is sufficient to discipline policy in adverse times. Monetary policy targets are not generally desirable as they hinder the ability of governments to smooth distortions. Allowing for the effective use of inflation during transitions is a key component of good institutional design. Debt ceilings are benign, but always dominated by deficit constraints. More pre-commitment to government actions is ineffective in curbing inefficiently high public expenditure.