In the US the Supreme Court is the final arbiter of how the law is interpreted. So, off the top of my head, there are at least 2 ways the effects of a judgement can be reversed. 1) The law can be specifically amended by congress and 2) the Supreme Court can make a future ruling which is different than it's original.

Of course, there are intricacies here. Especially in case 2 where the weight giving to legal precedence makes it unlikely.