The strength of a union depends, in part, upon its ability to mobilize its members not only in strikes but also in policing the collective agreement, filing grievances, and serving in the capacity of union stewards or committee members. Overflow crowds at union meetings, thousands of workers demonstrating in front of city hall, or every member wearing a union button all give the impression of unity and strength. Satisfied, highly committed members are more likely to support their union in strikes or political activities and to assist in organizing campaigns. Further, satisfied members serve as living advertisements of the advantages of union membership and so help win elections as well as public support generally. The reverse occurs when member are unhappy.