My bet is on Clarence Thomas retireing before the mid-term election next year.
Him and Ginsberg are both cancer survivors and are likely eyeing retirement. If I was in either of their shoes at their ages, I would be wanting to spend my limited time on this Earth with my family and the people I care about.
Then again, political power is a drug more addictive than heroin (studies have been done showing that that level of power over another person actually changes the endorphin output in the brain). There's a reason people often have to be forced out of political power (losing in an election, resigning because of a scandal, etc.). For an example, just look at Anthony Weiner. Any sane or rational person would have stepped away from the public spotlight after he disgraced himself the first time. The only kind of person that would continue to try and attain political power after such an ordeal, would be someone addicted to political power.