"Viability" in Lucas v. South Carolina Coastal Council and Planned Parenthood v. Casey

Justice Blackmun: "Viable is a good medical term, it isn't a legal term, but the lawyers have taken it over and the judges too."

Lucas v. South Carolina Coastal Council held that the government must provide compensation if a regulation deprives the owner of all "economically viable use" of his property. Lucas was argued on March 2, 1992 and Justice Scalia handed down the majority opinion on June 29, 1992. Here is a colloquy from that argument:

JUSTICE BLACKMUN: We're throwing around the term no economic viability of this property. . . . Viable is a good medical term, it isn't a legal term, but the lawyers have taken it over and the judges too. What do you mean by economic viability? . . .

MR LEWIS: So I think when you go down and you take a piece of property from uses down to no uses and from $1 million down to $0, you have a taking under our Constitution regardless of what–

JUSTICE BLACKMUN: That's hardly the medical definition of an old-time term of being viable.

Viability was apparently on Justice Blackmun's mind in Lucas. With good reason.

Planned Parenthood v. Casey was argued the following month on April 22, 1992, and was decided on June 29, 1992. And we know all-too-well that the Casey plurality adopted the viability line as part of the undue burden framework. (Well, everyone but Chief Justice Roberts, at least.)

I had never connected that two Supreme Court decisions, decided on the day, both turned on the concept of viability. In Lucas, the majority opinion per Justice Scalia, concluded that "viability" was a useful line for the Takings Clause; in dissent, Justice Blackmun thought "viability" was not a useful line. Meanwhile, in Casey, the plurality relied on the "viability" line, while the dissenters rejected this line. Of course, economic viability and fetal viability are very different concepts. Still, there is some disconnect.

Finally, Justice Blackmun's dissent in Lucas includes this sentence:

There is nothing magical in the reasoning of judges long dead.

Such a sentence is apiece with another claim Justice Blackmun wrote on June 29, 1992:

I am 83 years old. I cannot remain on this Court forever, and when I do step down, the confirmation process for my successor well may focus on the issue before us today.

Justice Blackmun likely missed the disconnect here as well.