Social capital and lateral constraint.

In order to exert power and maintain collective action, it is often necessary to mobilize one's social resources, ''one's relations'', and to know how to use them. This article examines this mobilization in terms of social capital conversion into lateral social constraints. The analysis is based on sociometric and three-way network data. More precisely, it shows how partners in a collegial organization, a corporate law firm, use leverage (i.e. their connections within the firm) to put pressure on each other. It is shown that actors mobilize their own social capital selectively, depending on the type of tie, the characteristics of the ''owner'' of the social resources and the relations between those involved. The development of lateral constraints thus appears to be the result of economic calculations, inextricably linked to partners' strategic culture and definitions of identities.