The Kaiser Family Foundation Associate Director at the Program on Medicaid and the Uninsured has compiled a short history of the federal government's position on the Affordable Care Act as well as the specific issues likely to be considered by the court. The article also discusses the possible consequences of the court's decision.
https://www.kff.org/health-reform/issue-brief/explaining-texas-v-u-s-a-guide-to-the-5th-circuit-appeal-in-the-case-challenging-the-aca/