MINNEAPOLIS — Referencing rulings to restrict capital punishment and changing sentiment within the Supreme Court, Justice Antonin Scalia said Tuesday he wouldn’t be surprised if the nation’s highest court invalidates the death penalty.

Scalia addressed capital punishment during a University of Minnesota Law School appearance in which he also made clear retirement isn’t in his near-term plans. The death penalty came up as Scalia described his judicial view that the Constitution is an “enduring” document that shouldn’t be open to broad interpretation — while sharing frustration that his colleagues too readily find flexibility in it.

Scalia said death penalty decisions from the court have made it “practically impossible to impose it but we have not formally held it to be unconstitutional.” Earlier in his remarks, Scalia said “it wouldn’t surprise me if it did” fall, a comment that drew scattered applause in the mostly full, 2,700-seat auditorium.

He said the high court has increasingly made it difficult impose the death penalty. He said rulings have added mitigating circumstances that must be considered or made it impermissible to automatically sentence people to death for certain crimes, such as killing a police officer.

The Supreme Court this month began its latest term and has already heard one death penalty challenge out of Kansas. While that case is limited in scope it was the first high court hearing on death penalty cases since a bitter clash over lethal injection procedures exposed deep divisions among the justices last term. The court intends to consider a case from Florida that questions whether judges, rather than juries, can impose a death sentence, especially when the jury is not unanimous in recommending death.

In his 30th year on the Supreme Court, Scalia is the longest-tenured current justice. The 79-year-old said he’s in no hurry to leave when asked by an audience member if justices should be forced to leave after a certain number of years rather than hold indefinite appointments.

“As soon as I think I’m getting lazier and I just can’t do the job as well, I’m going to get off there. I want to preserve whatever reputation I have,” Scalia said.