"Bilski also lines up perfectly for the scenario of a lost majority. It is a five-to-four decision. Justices Kennedy and Stevens are the authors of the principal opinions. The ruling took a long time to issue – it was argued in November but not decided until the last day of the Term – suggesting that something may have been amiss.
The Stevens opinion also reads as if it were originally an opinion for the Court […]. Further, the muddled vote of the majority’s fifth vote, Justice Scalia – who joined the majority in part and Justice Breyer’s concurrence in substantial part – suggests that he had significant difficulty in resolving the case. […] Another piece of evidence of rough compromise in Bilski is the Kennedy opinion itself. While it does decide the case, it is surpassingly narrow. It rejects the Federal Circuit’s “machine or transformation” test as the exclusive test of patentability and stops there. The Court does not attempt to provide further guidance, which is some evidence that five Justices could not agree on how to articulate an appropriate test. For all those reasons, it seems quite likely to me that Justice Stevens was originally going to author the Court’s opinion in Bilski but subsequently lost his majority to Justice Kennedy. […]
Finally, there remains the “so what” question. […] On the broadest level of whether the Court might revisit Bilski in a later case when Justice Scalia has the opportunity to consider the matter further, I think the answer is clearly no. In statutory cases like this one […] the Justices try to adhere to stare decisis. The decision in Bilski settles the question that business methods are patentable subject matter until Congress decides otherwise."
Source: http://www.scotusblog.com/2010/07/business-method-patents-nearly-bite-the-dust/