While Opposing Viewpoints in Context is an excellent resource for identifying a controversial issue to discuss and debate, other sources to find writing topics will include:
The NYT Opinion section offers many topics for discussion and debate.
Each individual print issue provides in-depth coverage of the most important issues of the day. Reports are written by experienced journalists, footnoted and professionally fact-checked.
TopicSearch
Bibliographic index for diverse current events literature on a wide variety of popular topics discussed in today's classrooms.