Jan Crawford at CBS got the scoop:
[Roberts] changed his position and formed an alliance with liberals to uphold the bulk of the law, according to two sources with specific knowledge of the deliberations.
Roberts then withstood a month-long, desperate campaign to bring him back to his original position, the sources said. Ironically, Justice Anthony Kennedy - believed by many conservatives to be the justice most likely to defect and vote for the law - led the effort to try to bring Roberts back to the fold.
"He was relentless," one source said of Kennedy's efforts. "He was very engaged in this."
But this time, Roberts held firm. And so the conservatives handed him their own message which, as one justice put it, essentially translated into, "You're on your own."
Naturally a lot of people are talking about this and I'm still skimming through all the commentary. But on page 2 of Crawford's article we're led to believe it is likely Roberts' vote was influenced by media coverage.
Rdbrewer at Ace's favorably compares French judges to Roberts, regarding potential outside influence. Roberts apparently absorbs news like a sponge. I tend to agree, at the very least, a Supreme Court Justice should avoid media coverage on the specific issue under consideration.
Randy Barnett at Volokh has more including video of Crawford on Face the Nation.
