In his dissent in District Attorney’s Office v. Osborne, Justice Souter joined the portion of Justice Stevens’s dissent that opined that Alaska had violated the Due Process Clause by failing to provide adequate procedural protections for the postconviction relief that it afforded. But he declined to opine at this time on “Osborne’s broad claim that the Fourteenth Amendment’s guarantee of due process requires our recognition at this time of a substantive right of access to biological evidence for DNA analysis and comparison.”

Souter’s broader explanation of his approach to substantive due process provides a particularly revealing insight into the mind of the liberal judicial activist. I offer some excerpts here (some citations omitted; emphasis added), and have decided, with one exception, to resist the urge to insert bracketed comments of my own:

Tradition is of course one serious consideration in judging whether a challenged rule or practice, or the failure to provide a new one, should be seen as violating the guarantee of substantive due process as being arbitrary, or as falling wholly outside the realm of reasonable governmental action. We recognize the value and lessons of continuity with the past, but as Justice Harlan pointed out, society finds reasons to modify some of its traditional practices, and the accumulation of new empirical knowledge can turn yesterday’s reasonable range of the government’s options into a due process anomaly over time.
A substantive due process claim requires attention to two closely related elements that call for great care on the part of a court. It is crucial, first, to be clear about whose understanding it is that is being taken as the touchstone of what is arbitrary and outside the sphere of reasonable judgment. And it is just as essential to recognize how much time society needs in order to work through a given issue before it makes sense to ask whether a law or practice on the subject is beyond the pale of reasonable choice, and subject to being struck down as violating due process.
It goes without saying that the conception of the reasonable looks to the prevailing understanding of the broad society, not to individual notions that a judge may entertain for himself alone [Why, of course not! It takes at least five of you], and in applying a national constitution the society of reference is the nation. On specific issues, widely shared understandings within the national society can change as interests claimed under the rubric of liberty evolve into recognition, see Griswold v. Connecticut (1965) (personal privacy); Lawrence v. Texas (2003) (sexual intimacy), or are recast in light of experience and accumulated knowledge, compare Roe v. Wade (1973), with Planned Parenthood of Southeastern Pa. v. Casey (1992).…
Just as attachment to the familiar and the limits of experience affect the capacity of an individual to see the potential legitimacy of a moral position, the broader society needs the chance to take part in the dialectic of public and political back and forth about a new liberty claim before it makes sense to declare unsympathetic state or national laws arbitrary to the point of being unconstitutional. The time required is a matter for judgment depending on the issue involved, but the need for some time to pass before a court entertains a substantive due process claim on the subject is not merely the requirement of judicial restraint as a general approach, but a doctrinal demand to be satisfied before an allegedly lagging legal regime can be held to lie beyond the discretion of reasonable political judgment.