WASHINGTON (Reuters) - Supreme Court Justice Antonin Scalia on Sunday renewed his criticism of Chief Justice John Roberts' reasoning in upholding President Barack Obama's 2010 healthcare law and also said the Constitution undoubtedly permits some gun control.

The 76-year-old Scalia - a leading conservative on the court who has served as a justice since 1986 - also was asked whether he would time his retirement in order to let a conservative future president appoint a like-minded jurist.

"I don't know. I haven't decided when to retire," Scalia told the "Fox News Sunday" program. "... My wife doesn't want me hanging around the house - I know that."

"Of course, I would not like to be replaced by someone who immediately sets about undoing everything that I've tried to do for 25 years, 26 years, sure. I mean, I shouldn't have to tell you that. Unless you think I'm a fool."

Roberts, also a conservative, sided with the nine-member court's four liberals in upholding the constitutionality of Obama's healthcare law, considered the Democratic president's signature domestic policy achievement.

Scalia joined in a sharply worded dissent on the day of the June 28 ruling and added to his criticism on Sunday.

A central provision of the law is the "individual mandate" that most Americans obtain health insurance by 2014 or pay a penalty. The ruling found that this penalty "may reasonably be characterized as a tax" and thus would be constitutionally permissible under the power of Congress to impose taxes.

"There is no way to regard this penalty as a tax. ... In order to save the constitutionality, you cannot give the text a meaning it will not bear," Scalia said.

"You don't interpret a penalty to be a pig. It can't be a pig."

Supreme Court justices rarely give media interviews. Scalia is making the rounds to promote "Reading Law: The Interpretation of Legal Texts," a new book he co-wrote.

Scalia brushed off Obama's comments aimed at the court regarding the healthcare law and a campaign finance ruling.

"What can he do to me? Or to any of us?" Scalia said. "We have life tenure and we have it precisely so that we will not be influenced by politics, by threats from anybody."

He was asked "why you push people's buttons every once in a while." Scalia said, "It's fun to push the buttons."

GUN CONTROL

Scalia wrote the high court's 2008 ruling that a ban on handguns in the U.S. capital violated the right to bear arms enshrined in the Constitution's Second Amendment.

In light of the July 20 massacre in which a gunman killed 12 moviegoers in Colorado, Scalia was asked whether legislatures could ban the sale of semiautomatic weapons.

He said the 2008 ruling stated that future cases will determine "what limitations upon the right to bear arms are permissible. Some undoubtedly are."

Scalia - a proponent of the idea that the Constitution must be interpreted using the meaning of its text at the time it was written - cited "a tort called affrighting" that existed when the Second Amendment was drafted in the 18th century making it a misdemeanor to carry "a really horrible weapon just to scare people like a head ax."

"So yes, there are some limitations that can be imposed," he said. "I mean, obviously, the amendment does not apply to arms that cannot be hand-carried. It's to 'keep and bear' (arms). So, it doesn't apply to cannons. But I suppose there are handheld rocket launchers that can bring down airplanes that will have to be ... decided."

Regarding the death penalty, Scalia said opponents want it struck under the ban on cruel and unusual punishment included in the Eighth Amendment of the Constitution.

"But it's absolutely clear that the American people never voted to proscribe the death penalty," he said. "They adopted a cruel and unusual punishment clause at the time when every state had the death penalty and every state continued to have it. Nobody thought that the Eighth Amendment prohibited it."

Scalia also took issue with decades-old Supreme Court precedent, saying the Constitution does not provide Americans with a right to privacy, despite a landmark 1965 ruling finding that it does. That ruling helped pave the way for the court's 1973 ruling legalizing abortion.

"There is no right to privacy - no generalized right to privacy," Scalia said. "No one ever thought that the American people ever voted to prohibit limitations on abortion. I mean, there is nothing in the Constitution that says that."

Scalia also was asked about his past criticism of rulings by Supreme Court colleagues in which he called them "folly" and "sheer applesauce."

"I don't know that I'm cantankerous," he said. "I express myself vividly."

(Reporting by Will Dunham; Editing by Bill Trott)