by Rui Esteves and Gabriel Geisler Mesevage (University of Oxford)
The possibility that politicians might act to further their private financial interests, as opposed to the general public interest, has led to the creation of conflict-of-interest rules in modern democracies. For example, the code of conduct of the British Parliament requires that MPs disclose private interests related to their public duties.
In the mid-nineteenth century, Parliament went further, and created a system for the approval of new major public works projects in which MPs with a conflict were barred from voting. But the effectiveness of these rules can be undermined if politicians agree to trade votes with their colleagues — a practice known as ‘logrolling’.
This research use a unique episode in the mid-nineteenth century to determine whether, and to what extent, British politicians traded their votes to further their private interests.
In the mid-1840s, hundreds of new railway companies petitioned the British Parliament for the right to build railway lines. It was Parliament’s responsibility to pick the railway lines they wanted to see built, and in this way shape the development of the modern British transport network.
Since many MPs were also investors in railroads, Parliament created a system of subcommittees, in which the applications of railways would be considered only by MPs without financial conflicts, and who did not represent a constituency that the railway was intending to service.
As a result of this system, MPs with vested interests could not vote for their preferred projects directly. But they could further their interests indirectly by trading their vote on another project with the vote of the MP overseeing the project in which they had an interest.
Drawing on methods from social network analysis, the study identifies all of the potential trades between MPs, and then test statistically for evidence of vote trading. The statistical evidence reveals significant collusion in the voting patterns of MPs who were deciding which railway lines to approve.
These findings reveal significant levels of vote-trading, with politicians coordinating their behaviour so as to ensure that the projects they preferred – which they were banned from influencing directly – were nonetheless approved by their colleagues. As much as a quarter of all of the approved projects were likely the result of this logrolling, and the economic costs of this behaviour were significant, leading to Britain creating a less efficient railway network.
This research highlights the importance of understanding politician’s private interests. Moreover, it illustrates how merely acknowledging conflicts of interest, and abstaining from voting when conflicted, may not resolve the problem of vested interests if politicians are able to collude. The findings shed light on a perennial problem; the methods developed to detect logrolling in this setting may prove useful for detecting vote-trading in other contexts.