"Policy" can refer to anything that establishes requirements, legal or otherwise.
Legal policy generally comes from laws, regulations, and court case decisions. These can be federal, state, or even in the example of regulations, municipal.
Sometimes you will have a specific policy in mind that you want to research (i.e. the Affordable Care Act, or Roe v. Wade). But often, we have just a topic that we are interested in, and need to find a related specific policy. Here are some tools to help discover policies by topic:
For interpretation, historical background, and implementation effects of a policy, you need to find secondary sources of information. The best analysis usually comes from materials written by scholars, or experts, and published either through a editorial review process, such as books published by academic publishers, or a peer-review process, used by many scholarly journals.
Google Scholar may also be a possibility, but use it very carefully. We lose the ability to have edited, verified collections with this product. To get the most full text, go to the Menu bar in the upper left, click on Settings, then click on Library Links. Choose University of Maine - Full Text.
These are sites that can assist in finding the actual policy, which is your primary source: