Many article databases will allow you to just search just the editorial/commentary sections. For example:
Check database Help screens for more information.
Also see Political Perspectives in Periodicals to help determine what stance (liberal, conservative, etc.) many popular periodicals often take.
Background and reference sources:
Blogs and other social media can help a researcher track both an event as it develops and popular interest in the event.
Using advanced search screens of search engines to limit to specific domains is another way to search blog sites such as wordpress, tumblr, blogger, etc.