Over at NRO, Benjamin Zycher offers up some speculation:
One trivial thought that I have not seen elsewhere: I wonder if the Left/Obama/Kathleen Sebelius didn’t shoot themselves in the backside when they decided to apply a chainsaw to the religious liberty of the Catholic hospitals, etc. That episode, I think, brought out in sharp relief the unprecedented degree of coercion inexorably inherent in Obamacare, the eagerness with which the Left employs it, and the thoughtlessness with which the Left is willing to destroy the institutions of civil society as they pursue their political goals. They really believe that people of religious faith are simpletons standing in the way of ever-greater individual dependence upon Leviathan.
And so I have a sense — but no direct evidence — that Kennedy and perhaps Roberts may have recoiled in horror from the prospect of Obamacare more deeply than otherwise might have been the case, as they were confronted with the prospective wholesale descent into economic fascism that is the very essence of Obamacare.
Putting aside the overwrought language, which is practically obligatory on the right these days, I wonder if there's anything to this? Roberts and Kennedy are both Catholic, and it's hardly a stretch to suppose that even if neither of them literally recoiled in horror, they certainly might have felt personally affronted by the whole contraception squabble. It's at least conceivable that it may have turned one or two wavering votes to uphold into likely votes to overturn.