Today's Supreme Court decision in Lawrence overrules the Court's 1986 decision in Bowers v. Hardwick, which had upheld the constitutionality of a Georgia law criminalizing consensual sodomy. Only three of the current nine justices were on the Bowers court. Then associate justice William Rehnquist and Sandra Day O'Connor both voted to support the Georgia law, joining an opinion authored by Byron White and also joined by Chief Justice Warren Burger and Justice Lewis Powell. John Paul Stevens, who joined today's opinion, authored a dissenting opinion in Bowers, and joined another dissent authored by Harry Blackmun which included Thurgood Marshall and William Brennan.
In one sense, then, today's decision was principally a reflection of the change in the court's membership rather than a great sea-change in the jurisprudence governing homosexual sodomy. Lewis Powell and and Byron White, two of the votes to sustain the Georgia law, were replaced, respectively, by Anthony Kennedy and Ruth Bader Ginsburg, who voted to overturn the Texas law. Stephen Breyer succeeded the like-minded Harry Blackmun. The only switch from overturning the law to sustaining it came from Clarence Thomas succeeding Thurgood Marshall.
One lesson to take from this: America benefitted from the Senate's decision in 1986 to reject Robert Bork's Supreme Court nomination. Bork was the first nominee to replace Powell; had he been confirmed, Bork would have almost certainly have voted to uphold the Texas law today. This would not have changed the result of the case, as there were six votes to reverse, but it would have prevented the Court from explicitly overruling Bowers, since Justice O'Connor refused to join that part of today's opinion.