Supreme Court Term Limits and Regular Appointments Act of 2020 This bill establishes staggered, 18-year terms for Supreme Court Justices and limits the Senate's advice and consent authority in relation to the appointment of Justices. Specifically, the bill requires the President to appoint a Supreme Court Justice every two years. If the appointment of a Justice would result in more than nine Justices on the Court, then the longest serving Justice, excluding Justices appointed before the enactment of the bill, is deemed retired from regular service and designated as a Senior Justice. Further, any Justice who has served a total of 18 years is deemed retired from regular service and may continue to serve as a Senior Justice. Senior Justices may continue to perform judicial duties assigned to them by the Chief Justice. However, a Justice who retires from regular service due to a disability may not serve as a Senior Justice. In the event of a vacancy on the Court, the Chief Justice must assign the Justice most recently designated as a Senior Justice to serve on the Court until the appointment of a new Justice. Additionally, the Senate's advice and consent authority is waived if the Senate does not act within 120 days of a Justice's nomination.