Before I head to Europe, let me expand, using thoughts Bill Otis presented to me, on why I think older judges are more likely than younger ones to decide cases based on sentiment.
Resisting sentimentality requires discipline and energy. Discipline can subside with the onset of old age. As Bill puts it:
By the time they get to their sixties, most talented lawyers have essentially made it in life, and the discipline required to climb the ladder subsides; the ladder has already been climbed. Loss of discipline is the catalyst for flabby self-indulgence, sometimes spelled “A-N-T-H-O-N-Y K-E-N-N-E-D-Y).
In other words, you go soft, or at least become more likely to give in to a softness that was already there. This does not universally happen to men, but you see often it.
Energy also diminishes, and it takes energy to resist prevailing cultural trends. Bill writes:
For virtually all my lifetime, liberalism has ruled the culture (including and importantly academia), and being a conservative just takes a lot of energy. For example, it is not only anti-male and anti-white bias that accounts for the fact that so many leftist airheads get jobs as professors; it’s that when you’re on board with the received liberal wisdom, you swim with the tide rather than against it.
Swimming against it produces harder thinking (which is one important reason conservatives like debates and more often than not win them), but it also requires a lot of energy. Sooner of later, for most people, it starts to run out.
I don’t see lack of discipline or energy (or sentimentality in general) in John Roberts’ jurisprudence. I think caution was the driver in the Obamacare cases. Anthony Kennedy, as Bill says, is another matter.
Particular Justices aside, it will be difficult for conservatives to ensure that Republican appointees remain solidly conservative as they reach old age.