Here are some series of books that include both pro and con points of view for a variety of topics. When searching the catalog, you can search by the titles of these series (ie: issues and controversies) or by your subject (ie: smoking bans). Try both ways to find the most resources on your topic, as relevant books may be in several different places in the library.
Gay Marriage by 
Animal Welfare by 
The Uninsured by 
Taking Sides by 
Modern Sports Ethics by