The Trump administration is actually going to propose that, per Politico:
The Trump administration is finalizing a long-awaited plan that it says will solve the opioid crisis, but it also calls for law enforcement measures — like the death penalty for some drug dealers — that public health advocates and congressional Republicans warn will detract from efforts to reverse the epidemic. . . .
According to language circulating this week, the Trump administration will call for the death penalty as an option in “certain cases where opioid, including Fentanyl-related, drug dealing and trafficking are directly responsible for death.”
As to the merits, I’ll just say that’s a bad idea and leave it at that. As to the political chances, I doubt Congress will be receptive. (Politico has a quote from a Republican senator gently declining to offer an opinion: “I don’t know if the president was serious or just said it off the cuff . . .”)
But I also think it would be vulnerable to a constitutional challenge. Rightly or wrongly, current Supreme Court precedent strictly limits the death penalty to the worst cases and bars “excessive” punishment; one case a decade ago even forbade it in the case of child rape.
To be sure, that case’s reasoning doesn’t map onto the current proposal very well. For instance, it completely sets aside “offenses against the State” including “drug kingpin activity,” and it doesn’t address a situation where the alleged victim willingly and knowingly consumed a dangerous substance. Further, the Court might look different if this policy becomes law and Anthony Kennedy retires before a challenge works its way through the lower courts.
Still: At this point, to let such a law stand, the Supremes would have to choose between (a) creating a system where you can execute drug dealers but not child rapists, adult rapists, and several other categories of violent criminals; and (b) overriding a bunch of precedent to create an entirely new test, in the service of letting the government execute drug dealers. Neither seems very appealing.