The Centre for Market and Public Organisation (CMPO) is a leading research centre, combining expertise in economics, geography and law. Our objective is to study the intersection between the public and private sectors of the economy, and in particular to understand the right way to organise and deliver public services. The Centre aims to develop research, contribute to the public debate and inform policy-making. CMPO, now an ESRC Research Centre was established in 1998 with two large grants from The Leverhulme Trust. In 2004 we were awarded ESRC Research Centre status, and CMPO now combines core funding from both the ESRC and the

We find the surprising result that the tax level is negatively correlated with the size of the Democratic majority in the interval in which the Democrats hold between 50 and 66 % of the seats in the state Legislatures. This negative relationship suggests the failure of a simple ideological model that had found some support in the literature, that the main determinant of the tax level is the extent of partisan control over the Legislature. We compare this model with an alternative: a separation-of-powers model in which ideology plays no role in determining the tax level. The driving force of our model is the overlap between the supporters of the Governor and the supporters of the legislative majority. The tax level at first rises and then decreases as the size of the ruling majority increases above 50 % of the seats, whether the legislative majority is of the same party as the Governor or from the opposition. This non-monotonic relationship is observed in the data and explained by our model.

Should the Federal government and the remaining American states adopt the line item veto? What are its effects? We use regression discontinuity design to claim that in states with the line item veto, divided government has a causal negative effect on the tax level. By investigating a panel of 38 American states from 1960 to 2006, we estimate a significant discontinuous increase of 13 % in the tax level as the party affiliated with the Governor in the state Legislature switches from being the minority party to being the majority. In the nine states that have block veto, we find no significant discontinuity in the tax level. We also find little evidence to suggest that the partisan identity of the majority party in the Legislature has a causal effect on the state tax level.

The Centre for Market and Public Organisation (CMPO) is a leading research centre, combining expertise in economics, geography and law. Our objective is to study the intersection between the public and private sectors of the economy, and in particular to understand the right way to organise and deliver public services. The Centre aims to develop research, contribute to the public debate and inform policy-making. CMPO, now an ESRC Research Centre was established in 1998 with two large grants from The Leverhulme Trust. In 2004 we were awarded ESRC Research Centre status, and CMPO now combines core funding from both the ESRC and the Trust.