It's difficult to predict which way a Supreme Court Justice will rule on "hot button" issues. However with John Roberts, you can see that he has been voting with the liberal wing of the Court more frequently as the newer Justices take the court more to the right.
If anything, it seems he is generally _not_ in favor of upsetting long standing precedents here. One might predict his vote will be to actually preserve the status quo on these "hot button" issues in the coming time.
Perhaps the other Justices will ache for the credibility gained with John Roberts being on their side and will thus agree to a narrowly worded opinion written by him -- it is a tantalizing possibility that you suggest.
But I think John Roberts being the leader of the institution might be keen to be on the "right side of history" on any highly controversial social issue and might just vote on the merits of the matter (as he sees it) -- even if that means he would be in the minority.
The phrase "right side of history" is difficult to explain but America should see what the rest of the world has decided regarding Women's reproductive rights. The trend seems to indicate that the direction of travel in America is against the rest of the world (developed and developing). This fact might be on Robert's mind as he decides what is the "right side of history."
---
P.S.
> you say, he will keep the opinion narrow
BTW I don't think I implied that anywhere in my response. I didn't express my opinion on what Robert's opinion might be _if_ he wrote the majority. Rather, I was generally saying that he would vote to preserve the status quo. The possibility to be able to write the majority opinion (and thus vote with the conservatives) option is definitely intriguing and was mentioned by you...
The Commerce Clause is a fairly central part of the “main constitution”, whether you like it or not.
Yes, it is.
It's not a popularly elected office, but then, neither is the Presidency. Certainly, every officer directly appointed by the President and confirmed by the Senate is political, legal terms of art about the two “political branches” notwithstanding.
Did that preserve the integrity of the court in your eyes? When the court itself admits the very concept of partisan gerrymandering is "incompatible with democratic principles", does this really preserve "equal justice under the law", which they claim [2] is their ultimate responsibility?