Clinton’s Supreme Court leverage lies in the short term: She could appoint a left-leaning justice to replace the solidly conservative Scalia, at which point the median justice would almost certainly become either Justice Stephen Breyer or Clinton’s appointee, either being reliably liberal. Prior to Scalia’s death in February, the moderate Justice Anthony Kennedy was the median justice.
Trump’s leverage, meanwhile, lies in the medium term: Trump’s conservative pick to replace Scalia would almost certainly restore the status quo before Scalia died, with Kennedy as the median. However, the three oldest justices — Ruth Bader Ginsburg (83 years old), Kennedy (80) and Breyer (78 in August) — are liberal or moderate. Thanks to the relentless, unidirectional drumbeat of time, Trump would have a good chance to replace at least one of those justices, pushing the court in a conservative direction. On the other hand, the oldest of the three sitting conservative stalwarts — John Roberts, Samuel Alito and Clarence Thomas — is only 68.
Fivethirtyeight.com – Oliver Roeder: Clinton And Trump Are Both Promising An Extreme Supreme Court