The Theory of Political Coalitions
| Author | William H. Riker |
|---|---|
| Subject | Political science |
| Publisher | Yale University Press |
Publication date | 1962 |
| OCLC | 00325635 |
The Theory of Political Coalitions is a book on positive political theory written by William H. Riker published in 1962. It uses game theory to formalize political theory. In it, Riker deduces the size principle. On its postulates, politicians are proved to form winning, minimal-size coalitions. The work runs contrary to a previous theory that they try to maximize their respective votes. Riker supposes that attracting more votes requires resources and that politicians run to win. A rational politician tries to form a coalition that is as large as necessary to win but not larger.
Minimal size coalitions
In a five-party system, if, after a general election, this representation is given:
| Party A | Party B | Party C | Party D | Party E | ||
|---|---|---|---|---|---|---|
| Number of representatives | 5 | 40 | 26 | 25 | 4 | Sum: 100 |
Three possible winning coalitions are possible:
| Party B and C | Party B and D | Party C and D |
|---|---|---|
| 40+26=66 representatives | 40+25=65 representatives | 26+25=51 representatives |
If it is now presumed that power will be divided according to strength within the coalition, the parties will prefer the largest relative size within the coalition. The result is that the coalition with C and D is the winning coalition. The largest party is thus kept from power.
Criticism
The assumption that governments will form on the base of minimal winning coalitions has a poor empirical foundation in Western European multiparty systems.
References
- "Book Review: The Theory of Political Coalitions". American Political Science Review 57 (2): 446–447. 1963. doi:10.2307/1952835.