Washington  - During three days of gruelling hearings before the US Senate this week, President Barack Obama's Supreme Court nominee Sonia Sotomayor did her very best to say as little as possible.

It has become something of a tradition in the last decade for nominees to the US high court - senators repeatedly probed on the most sensitive issues of the day, while Sotomayor deftly deflected questions on abortion, gun control, terrorism and gay marriage.

She said her judicial philosophy involved "fidelity to the law" and promised to be an impartial judge, rejecting charges from critics that the first-ever Hispanic to join the Supreme Court might show a bias towards minorities.

Sotomayor is virtually certain of being approved, most likely before the Senate begins a month-long recess on August 10. Even some conservative senators conceded she withstood the confirmation hearings well.

But there was one other nugget of news. During a fleeting exchange with Republican Senator Tom Coburn, Sotomayor left open the door for foreign laws and norms to be considered by US courts.

She was weighing into a critical topic that has sharply divided politicians, judges and legal scholars in the United States: Should US judges ever listen to the outside world to help them reach decisions?

US courts have always looked abroad in certain circumstances, such as with binding international treaties or even in some common law cases - like what kind of financial penalty to impose on a misbehaving company.

But should the US Constitution - the legal document that sits above all others in the country - ever be interpreted through the lens of international laws or norms?

It was a 2005 death penalty case that really set off a furore. The Supreme Court, in a 5-4 ruling, banned the state execution of anyone under 18 years, which at the time was legal only in Iran and the Democratic Republic of Congo.

Justice Anthony Kennedy, writing for the majority, argued that US "standards of decency" had evolved to the point that executions of juveniles should be considered "cruel and unusual punishment" under the US Constitution.

But it was Kennedy's suggestion that the "overwhelming weight of international opinion" stood behind his decision, which set off fireworks that continue to this day.

The ruling exposed a sharp rift on the Supreme Court itself. Some left-leaning justices like Ruth Bader Ginsburg have since backed Kennedy's view.

Conservatives slammed his reasoning: "Acknowledgement of foreign approval has no place in the legal opinion of this court," Justice Antonin Scalia wrote.

Most conservatives already believe the US Constitution must be taken literally - any suggestion that it is "evolving" is sharply rejected. The idea that international norms could be used to interpret the country's founding legal document was a step too far.

Michael Waxman, a law professor at Marquette University in Wisconsin, said the 2005 ruling really ramped up the debate. It virtually guaranteed that all future Supreme Court nominees would be asked by Republicans where they stand.

"It really got their blood boiling," Waxman said.

Sotomayor, for her part, seemed to choose a middle ground: Judges sometimes use foreign laws and international opinion to "educate themselves" on an issue, but she said it should never be a factor in the Supreme Court's ultimate decision.

"When I've seen other judges cite foreign law, they're not using it to drive the conclusion. They're using it just to point something out about a comparison between American law or foreign law," Sotomayor told the Senate Judiciary Committee.

But "foreign law cannot be used as a holding or a precedent or to bind or to influence the outcome of a legal decision interpreting the constitution or American law that doesn't direct you to that law," she said.

It was a "very interesting, tricky answer," said Waxman. "It leaves open a crack in the door" to listening to international opinions, though she rejected the idea that it would impact her decisions.

Sotomayor, 55, is unlikely to spur any major shift in the Supreme Court's debate. She is considered a moderate, left-leaning judge who will be replacing someone with a similar mindset - the retiring Justice David Souter.

The "major battle" over international norms, as well as a whole host of other issues, will begin if a more conservative-leaning justice retires while Obama is in office, Waxman said. (dpa)