"We are not supposed to be an assembly of gentlemen who have no interests of any kind and no association of any kind. That is ridiculous. That may apply in Heaven, but not, happily, here."
---Winston Churchill, characterizing the House of Commons in 1947
Winston Churchill became world famous as Britain's Prime Minister during World War II, but as the above quote suggests, his attitude towards conflicts of interest was merely that of a typical Conservative member of the House of Commons. Two Harvard political scientists have found that serving in Parliament roughly doubled the wealth of Conservative MPs but had no discernible effect on the wealth of Labor MPs. Conservative MPs profited by outside work as directors, consultants, and lobbyists, both while in office and afterwards. These results support conventional wisdom but also suggest that Conservatives' financial gains were larger than typically assumed. Details below.
In "MPs For Sale? Estimating Returns to Office in Post-War British Politics" Andy Eggers and Jens Hainmueller present results of their analysis of probate records of successful candidates for Parliament in 1950-70. They compare their wealth at death to a control group of candidates who narrowly lost. Their reasoning is that in closely contested elections the characteristics of narrow losers are very similar to the winners in terms of demographics, as well as in terms of such hard-to-measure factors as charisma or well-connectedness.
Their key finding: Conservative MPs roughly doubled their wealth by serving in Parliament. The median Conservative MP bequeathed around 532,000 pounds (in 2007 prices) but would have left around 257,000 pounds if not elected. By contrast, the median Labor MP bequeathed around 254,000 pounds, the Labor losers about 250,000. (Minor parties were not part of the analysis). For Conservatives (but not for Labor), frontbanch or Cabinet status was associated with even larger income gains, but the statistical evidence here is not as strong.
These differences have persisted. In 2007 91% of 333 Labor MPs reported zero outside income, while only 66% of 197 Conservative MPs did. (These data exclude income from board of directors memberships, which if included would widen the disparity between Labor and the Conservatives).
Viewing government as an appropriate source of private wealth seems to be something that conservatives in the United States have in common with their British counterparts. Public awareness of this in Britain was a factor in Labor's electoral success in the 1990s. Perhaps a similar pattern is beginning to occur here.