The most outspoken judge on the US Supreme Court has defended the use of some physical interrogation techniques.
Some torture may not be "cruel and unusual punishment", says Scalia
Justice Antonin Scalia told the BBC that "smacking someone in the face" could be justified if there was an imminent threat.
"You can't come in smugly and with great self satisfaction and say 'Oh it's torture, and therefore it's no good'," he said in a rare interview.
He also accused Europe of being self-righteous over the death penalty.
Justice Scalia is known as the most acerbic member of the Supreme Court, and is often described as the most conservative of the court's judges.
In the interview with the Law in Action programme on BBC Radio 4, he said it was "extraordinary" to assume that the ban on "cruel and unusual punishment" - the US Constitution's Eighth Amendment - also applied to "so-called" torture.
"To begin with the constitution... is referring to punishment for crime. And, for example, incarcerating someone indefinitely would certainly be cruel and unusual punishment for a crime."
Justice Scalia argued that courts could take stronger measures when a witness refused to answer questions.
"I suppose it's the same thing about so-called torture. Is it really so easy to determine that smacking someone in the face to determine where he has hidden the bomb that is about to blow up Los Angeles is prohibited in the constitution?" he asked.
"It would be absurd to say you couldn't do that. And once you acknowledge that, we're into a different game.
"How close does the threat have to be? And how severe can the infliction of pain be?"
Justice Scalia also mocked European criticism of the US use of the death penalty.
"If you took a public opinion poll, if all of Europe had representative democracies that really worked, most of Europe would probably have the death penalty today.
"There are arguments for it and against it. But to get self-righteous about the thing as Europeans tend to do about the American death penalty is really quite ridiculous."
His position was fiercely criticised by Professor Conor Gearty of the London School of Economics, one of Britain's leading experts on human rights law.
"Antonin Scalia works hard to protect himself from having to think seriously about torture," he said.
"His devices are quite obvious, the idea of a smack on the face - rather than sensory deprivation, or waterboarding or any of the Abu Ghraib images - and the comment about 'so-called torture'..."
Professor Gearty accused Justice Scalia of creating a "nightmare scenario of mass destruction that all defenders of torture so need, to hide the fact that the reality of torture will be quite different".
Law in Action will be broadcast at 1600 on Tuesday 12 February on Radio 4. The programme is also available as a podcast from bbc.co.uk/podcasts