After you have selected a topic, you will need to do a preemptive check to locate a substantial article on your subject.  One place to begin your search is in Google Scholar, Index to Legal Periodicals & Books Full Text or Hein Online.  Other resources for a preemptive check include American Law Reports (ALR) which is located in the Grand Reading Room on the 5th floor of the Law Library, or you can check ARLs electronically on Westlaw or Lexis. 

If your topic covers a discipline beyond law, you can also search for journal articles in that area.  To research non-legal topics, go to the UW Library Web site, locate the tab for databases, select "subject," and select the appropriate topic or check Social Science Research Network (SSRN), which has both legal as well as non-legal scholarly journal articles.