How do case law and statutory law interact in the American legal process?

Your company has been sued for product liability and has a case going to trial next week. In researching some of the applicable cases, you have found some favorable language that interprets the applicable statute. Your supervisor has asked you to write a summary of the circumstances under which the judge should rely on existing case law to determine the intent and purpose of a statute.

How do case law and statutory law interact in the American legal process? Does one trump the other or take priority? When there is a statute and case law that apply, does the court have any discretion in how to apply the law to your case