Goosegg posted:But here, there are no merit rulings so the underlying law didn't change; it was merely "clarified" before the court ruled. If there had been rulings on the merits - by this court or any other - a new law would change the result. But here, there is no result to be changed, so the rulings are prospective based on the law (but, retrospective on the facts).
This isn't a case of the court ruling a contract unenforceable retroactively; it's simply applying an ambigious law to the facts in a way which is in harmony with the now amended law - in which the new law specifically makes clear the new congressional intent (whether applied retroactively or not).
New laws do impact cases - statue of limitations changes make former non-actionable behavior actionable for example. But it's an area in which I lack true depth of knowledge and, therefore, will not be a hill I die on!
There is some merit to the notion that when a court looks at the entire legislative history of an act, they naturally compare the current clarification with past application and, if it matches closely, they will implicitly give it weight. So, yeah, any legislation like that would likely affect the current cases.