1. “not entirely comparable” is an understatement. It’s not a state. It can’t “seceed.”

2. Sotomayor is ethnically Puerto Rican. She was not born there. A strict reading of your formulation (“the idea that someone who could be appointed to the Supreme Court who apparently doesn’t (or at least didn’t) believe that her people should be a part of the United States seems a bit odd.”) would suggest that Scalia and Alito don’t belong on the Court unless they thinks the U.S. should annex Italy.

One definition of the verb “to secede” is “To split from or to withdraw from membership of a political union, an alliance or an organisation”; Oxford’s New American (the OS X “Dictionary”) gives “withdraw formally from membership in a federal union, an alliance, or a political or religious organization.” I think Puerto Rican independence would fall under either of these definitions, even if the exact nature of its secession would differ from a state seceding.

And as far as I know, Scalia and Alito have never written anything that advocated the departure of any territory from the United States. And Italy has never been part of, or governed by, the United States. Sotomayor’s ethnicity is actually rather beside the point.

1. That’s not exactly the defn. of secede that we mean in this context, though. It would certainly differ, in a huge way. The politics of PR’s status is complex. Some want statehood, some want independence, some want the status quo. The issue is a live one, and yet we rarely treat it in the same way that we would a state leaving the union, precisely because it isn’t.

2. How is her ethnicity beside your original point? Puerto Ricans are “her people” only because of her ethnicity? But if it is beside the point, you seem to be suggesting that, as a qualification for legal office, one must prefer holding onto all territory to ceding it, period. But the U.S. has routinely given up territories (Panama Canal zone, to take the most recent example). Why is supporting such a policy odd for the Court?

1. Actually, we rarely treat it at all. But given that fewer Puerto Ricans seem to favor independence than Americans favor their own states’ secession, if the polls and Puerto Rican plebiscites are to be believed, both can be fairly criticized as comparably “fringe” positions.

2. Sotomayor likely wouldn’t even be an American citizen if it weren’t for the fact her Puerto Rico-born parents were American citizens by virtue of Puerto Rico’s association with the United States (otherwise, I’d imagine it would be similarly hard to legally emigrate from Puerto Rico to New York as it is to emigrate from the Dominican Republic or Mexico). So it’s rather more relevant than Alito and Scalia’s more distant Italian ties or the other members’ ties to their ancestral homelands in that regard.

I think it’s also relevant in the sense that Puerto Rico’s status (instead of, say, Italy’s) might rightly come before the court in the future; for example, would she have voted to grant cert in the various cases styled Igartua v USA dealing with the alleged right of American citizens residing in Puerto Rico to have a role in selecting presidential electors?

Authority for above: Research 2000 poll of Texans in the wake of Perry’s idiocy, versus here for the 1998 plebiscite.

I think you’re pushing this harder than you can justify. Your position now is pretty far removed from talk about “her own people” in your original post.