The McKesson case, in section E. of chapter 10, is a multifaceted case. Although in the section called "Prospective or Retroactive Relief and other Legal Remedies," the case also contains a great discussion of how a state tax can be determined to be unconstitutional, that is, in violation of the United States Constitution. Describe both of these issues: how the state tax was determined to be unconstitutional, and what the Court had to say about the appropriate remedy