"Four sitting justices have served for longer than two decades — Anthony M. Kennedy the longest at nearly 29 years, followed by Clarence Thomas, Ruth Bader Ginsburg and Stephen G. Breyer. Both Kennedy and Ginsburg are in their 80s.

If Kennedy, the court's swing vote, or Ginsburg, its liberal anchor, were to retire soon, Trump would have a clearer opportunity to significantly shift the court’s ideological balance. "