Why did "sources familiar with the private Supreme Court deliberations" talk to CNN about the Census Case?

What do we make of the Department of Commerce leak? And did Justice Sotomayor lose the majority opinion in Gundy?

Shortly after NFIB v. Sebelius was decided, Jan Crawford dropped a bombshell report: Chief Justice Roberts switched his vote. Over the ensuing weeks, months, and years, more information was released from the Court about how, why, and when he changed his vote. Why was this information leaked? Generally, private information is revealed for self-serving purposes. Perhaps the conservatives were frustrated with the Chief's vote. Perhaps the liberals were trying to rehabilitate the Chief. We may never know for sure.

Today, Joan Biskupic of CNN dropped another bombshell report:

Chief Justice John Roberts cast the deciding vote against President Donald Trump's attempt to add a citizenship question to the 2020 census, but only after changing his position behind the scenes, sources familiar with the private Supreme Court deliberations tell CNN. . . .

After the justices heard arguments in late April, Roberts was ready to rule for Ross and the administration. But sometime in the weeks that followed, sources said, Roberts began to waver. He began to believe that Ross' rationale for the citizenship question had been invented, and that, despite the deference he would normally give an executive branch official, Ross' claim had to matter in the court's final judgment, which Roberts announced on June 27.

I pose the same question for Department of Commerce as I did with NFIB.  Why was this information leaked? What is the potentially self-serving purpose for revealing this information? And why was it leaked now, nearly three months after the case was decided?

This leak reaffirms a principle we are all too-familiar with: the Chief Justice can be swayed after a case is submitted for argument. In 2012, perhaps he was moved by certain political currents concerning the ACA. (I wrote about the aftermath of oral arguments in Part VII of Unprecedented.) And in 2019, perhaps Chief Justice Roberts was affected by the release of the Hofeller files. Biskupic cannot say for sure:

It is not known how Roberts might have been influenced in the census dispute by information that emerged on May 30 in news reports and court filings that appeared to reinforce the possibility that Ross had not been truthful.

This leak provides further encouragement to those who try to work the courts after a case is submitted. Though, to be frank, no one needed this reassurance. At this point, all court watchers know Roberts's modus operandi by now.

Why was this information leaked? Was it a move from the right to embarrass the Chief, or put pressure on him ahead of this significant term? If so, why wait so long? It would not have made much sense to release this information in the immediate aftermath of Department of Commerce, because there was still a chance that the Trump Administration would try to issue a new policy. Though, soon enough that plan was abandoned.

Finally, a note on sourcing. Who are "sources familiar with the private Supreme Court deliberations"? There are at least two source (plural). They could be a mix of (1) Justice(s), (2) clerk(s), (3) non-Court personnel in contact with a Justice, or (4) non-Court personnel in contact with a clerk. I am skeptical Biskupic would run a story of this magnitude based solely on information from people in category 3 or 4. There is likely someone in category 1 or 2.

Towards the end of her report, Biskupic also drops a bombshell about Gundy v. United States, a case of far greater significance than the one-off Department of Commerce:

But the decision-writing process is fluid. As they draft and share opinions, justices sometimes change positions, subtly in ways that affect parts of the legal reasoning undergirding an opinion, or more dramatically in ways that affect the entire outcome.
Sources familiar with deliberations say that two such noteworthy changes occurred last session, in the census controversy and in a dispute over the validity of a federal sex offender registration act.
In that latter case, the justices upheld the act by a 5-3 vote. (Justice Brett Kavanaugh did not participate in that case heard on the second day of the new session because he was not yet confirmed for the bench.)
Earlier in those negotiations that began in October and stretched until June, a different five-justice majority was headed in the opposite direction, toward invalidating the law and potentially limiting the authority of Congress to delegate power to another branch of government. (The 2006 Sex Offender Registration and Notification Act gave the attorney general authority to determine how the law applies to some convicts; Roberts, who dissented from the final decision preserving Congress' delegation power, did not switch his vote in this case, Gundy v. United States.)

This passage is far more perplexing than the discussion about Department of Commerce. In Gundy, the short-handed Court upheld the SORNA provision by a 5-3 vote. Justice Gorsuch dissented, joined by the Chief Justice, and Justice Thomas. Biskupic tells us that Roberts did not change his vote. And I am doubtful Gorsuch or Thomas would have changed their vote. Even if Justice Alito originally joined the conservative trio, there still would not have been a five-member majority. Therefore, if Biskupic's reporting is correct, one member of the liberal wing–the Ginsburg Four!–would have originally gone along with the conservatives to declare unconstitutional the SORNA provision.

My theory: Justice Sotomayor was given the original assignment. She was the only Justice who did not write an opinion from the October sitting. Perhaps she tried to craft a narrow, pro-defendant opinion that would have killed the SORNA regulation, without opening up a new front against the administrative state. At that point, Justice Kagan wrote a dissenting opinion for herself, and Justices Ginsburg and Breyer. However, something changed. Perhaps Justice Gorsuch circulated a concurring opinion (which would become his dissent). At that point, the conservatives may have refused to join the Sotomayor opinion, because it was too narrow, and perhaps foreclosed future expansions of the nondelegation doctrine. Or, it is even conceivable that Justice Sotomayor did not want to give credence to the Gorsuch position, abandoned her own majority opinion, and decamped to Kagan's bloc! At that point, the Court would have fractured 4-4. To avoid that outcome,  Justice Alito bit the bullet and did something he had never done before: join four liberal Justices. (Could Justice Kagan have withdrawn her own opinion, forcing a 4-4 affirmance?!) But doing so ensured that the Gorsuch opinion would be published, and, with Justice Kavanaugh on the bench, become a majority opinion.

What do you think?