The passage of time influences the content of the law and therefore also the validity of legal arguments. This is true even for charter-arguments, despite the widely held view that constitutional law is made to last. In this paper, I investigate the reason why the sanctity-of life argument against physician assisted suicide lost its validity between the Supreme Court decision in Rodriguez v. British Columbia in 1993 and Carter v. Canada in 2015. I suggest that a rhetorical approach to argument evaluation is the best basis for a satisfying explanation