Obituary: William H. Riker

William Harrison Riker, political scientist and historian: born Des Moines, Iowa 1921; Professor of Political Science, University of Rochester, New York 1962-93; President, American Political Science Association 1984; married 1943 Mary Elizabeth Lewis (one son, two daughters); died Rochester, NY 26 June 1993.

WILLIAM H. RIKER was one of the founders of rigorous political science. Most of what was written in the subject between the 1780s and the 1950s was purely descriptive, although often laced with the author's opinions about what ought to be done. Most teachers of politics had trained as historians, lawyers, or philosophers, and their work reflected the strengths, weaknesses and characteristic prejudices of their parent discipline.

The first signs of revival came with the 'behavioural revolution' of the 1950s. This was important but limited. It replaced confident assertion about what the people thought by careful investigation of what they actually thought. But political science still lacked any predictive tools, or even bases for intelligent generalisation. Riker was one of the first suppliers. His The Theory of Political Coalitions (1962) predicted that the likeliest coalition to form was that which commanded the smallest possible number of votes in the legislature sufficient just to win. The Riker formula would have predicted (Conservatives - Maastricht rebels + Official Ulster Unionists) as the exact winning coalition to carry the Maastricht Treaty.

Riker then turned his attention to social choice theory. This is best known for its startling 'impossibility theorems': for instance, that no voting procedure can satisfy some minimal requirements of fairness and logicality without possibly generating a dictator. Riker was only the second person to put these theorems to work, in a positive way, in politics. (He also rescued the reputation of the first, the Scottish economist Duncan Black, 1908-1991.)

His masterpiece, Liberalism against Populism (1982), shows how deep the impossibility theorems are and how badly they damage most assertions about democracy. It uses social choice theory to show how the issue of slavery in American national politics was deliberately put to sleep in 1787 and just as deliberately awakened by Abraham Lincoln and his supporters in the 1860 Presidential election. Lincoln won the most important election in American history with less than 40 per cent of the vote. Riker showed how, under different electoral systems, other candidates might have won, and how Lincoln was in a 'cycle' whereby he had majority support over John Bell, who would have beaten Stephen Douglas, who would have beaten Lincoln.

Bill Riker visited Britain twice in recent years. He was a delight at seminars - full of enthusiasm and utterly unpompous. For his 70th birthday, his friends commissioned a sweatshirt showing the frontispiece of Hobbes's Leviathan, with the head of the king whose body is made up of thousands of followers replaced by the flowing white locks of WHR It was an apt metaphor for the influence of the cleverest and kindest of political scientists, whose influence spread worldwide from cold, sleepy, Rochester.