Choosing a place to start researching is an important part of finding sources for your literature review. These databases should help you get started.
Reference books specific to your topic can give you a good introduction to what you need to know as well as point to high quality resources.
Try some of these strategies with your research question:
To integrate your "research project into existing political science literature" as your assignment requires, think of your project as a conversation between you and other scholars. You want to learn what other scholars have said about your topic so you can add to the conversation without repeating what others have said.
Once you've found a helpful article, search for it in Google Scholar, then click the Cited by link to see the conversation your article has generated.
Some databases will link to references cited in a particular article, which will help you find previous research.
Look for the works cited at the end of a book or article, then...