Washington ? The Supreme Court took up the far-reaching question Tuesday of whether the executive branch has broad constitutional powers to solicit outside advice and make policy decisions without being forced to disclose details of the deliberations to the public.

In a lively oral argument on one of its most important cases this term, the court appeared divided. The justices grilled lawyers for the government and two public interest groups about whether Vice President Dick Cheney’s energy task force should be required to disclose details of its deliberations three years ago on a national energy policy.

The two groups, Judicial Watch and the Sierra Club, had won a lower court decision that would allow them to obtain information about the inner workings of the task force.

The organizations had sued to enforce disclosure, alleging that the energy industry, including bankrupt Enron Corp., had undue influence in formulating the Bush administration’s energy policy.

In response, the administration made an argument that the Constitution protects the president and vice president from revealing any details.

The case went to the high court after an appellate court upheld the district court’s decision. If the administration loses in the Supreme Court, Cheney would have to reveal records of the task force in the middle of a presidential campaign. A decision is expected by the end of June.

“This is a case about separation of powers,” said Solicitor General Theodore Olson, arguing for the government. “Congress may neither intrude on the president’s ability to perform these functions nor authorize private litigants to use the court to do so.”

Among those peppering both sides with questions was Justice Antonin Scalia, who stirred up a political storm when it was revealed he went on a duck-hunting trip to Louisiana with Cheney, an old friend, shortly after the court agreed to hear the vice president’s appeal. Scalia refused to recuse himself from the case.

Scalia also has faced criticism for a 2001 hunting trip coinciding with a visit to Kansas University, which was arranged by Stephen McAllister, dean of the KU law school, shortly before the Supreme Court was to rule on two cases in which McAllister was lead attorney.

In his questions, Scalia expressed sympathy with the administration’s position, challenging an argument by the two public interest groups that energy industry interests had “de facto” membership on the task force. They had no power to vote on the decisions, the justice said, and so could not be classified as members.

Scalia also said the president has the right to refuse to reveal details of such discussions. “He has the power as an independent branch to say, ‘No, this intrudes too much upon my powers. I will not do it,”‘ he said.

At another point, Scalia said, “I think executive privilege means whenever the president feels that he is threatened, he can simply refuse to comply with a court order.”