It may be helpful to have your students do some background reading and reporting on their topic. It's hard to evaluate new information when you don't know much about a topic. You might ask your students to tell you:
Events related to their topic. Could be recent or more long term depending on the topic
Major players, including both people and organizations.
Major organizations will likely have websites that students will end up using as information sources. Often these have a particular point of view and students should be aware of that when they decide to use information from these sources. Having the students list these in advance lets you bring up this concern and encourage them to look for sources from a variety of information sources.
Viewpoints. May be more complex than just pro/con. There may be differing solutions to a particular problem. Or a disagreement about whether there is a problem.