The provision of public services through national legislatures gives legislators the chance to fund locally beneficial public projects using a shared national tax base. Nationally financed and provided local (congestible) public goods will be purchased at a subsidized price below marginal cost and may be inefficiently too large as a consequence. An important assumption behind this inefficiency is that national legislators in fact demand more of the locally beneficial project as the local price for projects declines. This paper provides the first direct test of this important assumption using legislators\u27 project choices following the passage of the Water Resources Development Act of 1986 (WRDA\u2786). We find legislators\u27 chosen water project sizes do fall as the local cost share rises, with a price elasticity of demand ranging from β0.81 for flood control and shoreline protection projects to β2.55 for large navigation projects. The requirement of WRDA\u2786 that local taxpayers contribute a greater share to the funding of local water projects reduced overall proposed project spending in our sample by 35% and the federal outlay for proposed project spending by 48%