Chief Justice John Roberts wrote the opinion largely upholding the Affordable Care Act, rankling conservatives.
Without disclosing how she would have voted, O'Connor, a moderate who served as the court's swing vote during her tenure, said on CBS' "Face the Nation" the case was a difficult one and the 5-4 vote "tells that they don't always agree, and that's what it should be. For goodness sake, that's why you have a court. And you have nine members, so it's uneven; you're not going to split evenly."
O'Connor noted that any time a controversial decision is issued near a presidential election, the decision looks political, adding the 2000 Bush vs. Gore decision that halted the counting of ballots in Florida might have dimmed the public's respect for the court.
"In the past, when the public is asked about the three branches of government, the court has generally had -- the judicial branch has had the highest respect among the three," O'Connor said. "And now it's about the same for all and it's all down. So that's a great disappointment to me to see. I'm sorry."