In a speech last week at the University of Minnesota, Supreme Court Justice Antonin Scalia said "it wouldn't surprise me" if the death penalty became a thing of the past in the United States.
He could even imagine it happening during his tenure, he said — which, considering he's 79, would presumably be soon.
• More: Scalia on the death penalty
But how close is the Court to actually ruling capital punishment unconstitutional?
MPR News' Kerri Miller spoke to David von Drehel, Time Magazine editor-at-large, and Carol S. Streiker, professor of law at Harvard Law School, about the realities of the issue. Drehel is the author of "Among the Lowest of the Dead," a history of the modern death penalty.
"I would say within 20 years, absolutely," Streiker said of the end of capital punishment.
Drehel and Streiker discussed many of the issues that would contribute to such a ruling.
Public support is waning
Public support for the death penalty has been dropping since the 1990s, when a record high of 80 percent of Gallup poll respondents favored capital punishment. In the most recent poll completed this month, only 61 percent were in favor.
Part of this drop can be attributed to the drop in the national murder rate. "The fact that the murder rate has fallen from record highs to around record lows takes that boiling pot off the stove in a sense," said von Drehel.
The Supreme Court has the tools it needs to eliminate it
The Supreme Court already has the legal tools it would need to abolish the death penalty, according to Streiker.
"The Court has an 8th amendment doctrine that says punishments are cruel and unusual if they violate evolving standards of decency," Streiker said. "And the court looks to developments on the ground: What's happening in the world? The death penalty in America is really on life support now."
The system of carrying out executions is flawed
With botched executions in the headlines, many people are asking questions not about the constitutionality of the death penalty but about the actual logistics of carrying it out.
In some states, the process is so complicated and controversial that it is rarely used.
"What we have now is a system in which after a person is sentenced to death, the likelihood that they'll actually be executed is minuscule," von Drehel said. "There are over 750 inmates on death row in California, and there have been just 4 executions in the last 10 years. The same sort of thing is true in Florida, in Pennsylvania — it's true all across the country."
The rate of error is troubling
The risk of executing innocent people was enough to lead Illinois governor George Ryan to clear out his state's death penalty in 2003. "The facts that I have seen in reviewing each and every one of these cases raised questions not only about the innocence of people on death row, but about the fairness of the death penalty system as a whole," Gov. Ryan said at the time.
How high is the error rate?
As many as 4 percent of inmates on death row are wrongly convicted, according to the first major study on the subject, published in 2014.
"We can't reach the level of certainty that our Supreme Court has said is necessary, and we've tried for 40 years," von Drehel said.