The plaintiffs in King targeted insurance subsidies for Americans who enrolled through Obamacare's federally-run exchanges, relying on a gibberish legal pretext and hoping that the Supreme Court's majority of Republican justices would vote it through. Opponents of the law then spent the next several months in an uncoordinated media pressure campaign to secure their ruling.
The Court's Democratic minority -- Justices Ginsburg, Breyer, Sotomayor, and Kagan -- were always going to rule against the case, since it was obviously stupid and since they are Democrats who want the law to succeed.
But Republican Chief Justice Roberts has never opposed the ACA in principle, and Republican Justice Kennedy has only voiced modest, narrowly tailored objections. In the end, both joined the Court's Democrats to defeat their more partisan colleagues, Justices Alito, Scalia and Thomas. Ultimately, a number of factors influenced their defection:
- A relative lack of social and financial investment in an adverse ruling -- for instance, fewer close friends and loved ones in radical right-wing circles;
- Instinctive judgments about how various rulings would impact their legacies;
- Partially unresolved Oedipus complexes involving an incomplete reconciliation and identification with their fathers, expressed as an inclination towards rebellion and contrarianism;
- What they had for breakfast the morning they settled on an opinion.
Both Justices will presumably try to compensate for this decision with a ruling for Republicans in a completely unrelated case.