The Bush administration's top lawyer told the Supreme Court on Tuesday that the Constitution gives the president and vice president near-unassailable authority to make policy without disclosing who or what influences it.

The case is one of several tests of presidential power this term and, like the others, it carries the potential for a strong rebuke of the president's assertion of power.

Last week, the government was before the high court defending its indefinite detention of foreign enemy combatants at the U.S. naval base at Guantanamo Bay, Cuba. On Wednesday, the court will hear two cases that test whether the president can hold American citizens indefinitely, without access to lawyers or courts.

Defending Vice President Dick Cheney's refusal to release documents from his task force on energy policy, Solicitor General Ted Olson said Tuesday that the Constitution's mandated separation of powers prevented Congress or the courts from even attempting to pry into the executive's business.

Olson told the justices that a 1972 law that publicizes the work of government employees in forming White House policy doesn't extend to nongovernment advisers. And even if it does, he said, it's unconstitutional.

"The Constitution explicitly commits to the president's discretion the authority to attain the opinions of subordinates and to formulate recommendations for legislation," Olson told the justices. "Congress may neither intrude on the president's ability to perform these functions nor authorize private litigants to use the courts to do so."

The justices seemed sympathetic to the thrust of Olson's arguments. But they appeared more split on how to define when the president should enjoy such sweeping secrecy and whether the government had improperly bypassed lower court review to obtain a high court ruling.

Justice Antonin Scalia, who'd been asked to step down from the case because he went duck hunting with Cheney earlier this year, questioned lawyers from both sides. But he was defensive of the administration's right to keep much of its work secret, a position that's consistent with his views on executive privilege.

Lawyers for the Sierra Club, an environmental group, and for Judicial Watch, a conservative legal watchdog, sued the administration in 2001 to find out what role energy industry lobbyists and executives played on Cheney's task force. In particular, they allege that people such as former Enron chief Kenneth Lay -- who's close to President Bush and Cheney -- were de facto members of the task force whose contributions to the administration's energy policy should be made public.

The case is rife with political implications because critics already have said the administration is cozy with energy interests.

In the case, the administration has staked out as broad a position as it has in asserting the right to designate people as "enemy combatants," and has refused to yield. The government has maintained that courts don't even have the right to ask the vice president for the information, let alone obtain it.

The president shouldn't be required to assert his executive privilege to deny the information, Olson said. Instead, there should be a "presumption of regularity" about how he conducts his affairs that rebuffs any complaints except those of a criminal investigation.

The administration first tried to have the lawsuit dismissed. When that was refused and documents were requested from the vice president's office for use at trial, the administration requested an unusual right to appeal before court proceedings took place. When that was denied, the vice president tried another procedural end- around to avoid disclosure. That failed, and the case was appealed to the Supreme Court.

Olson seemed to find sympathy for many of his points among the justices, and probably bolstered his argument by drawing a comparison between the president's privilege and the court's.

What would happen, Olson asked, if Congress had applied the 1972 law to the court or to itself, "and then allowed litigants to bring them into court to explain why they wouldn't produce information?"

The justices pressed lawyers Alan Morrison and Paul Orfanedes, representing the Sierra Club and Judicial Watch, to define when the 1972 law compels disclosure of outside advice and when it doesn't.

If the justices were to take the view that nearly every contact with outsiders by the executive branch is public, "you will stop every lower-level official in government, when he's creating legislative policy, from getting on the phone and calling up whoever he pleases," Justice Stephen Breyer said.

Morrison responded that the law applies only "if you have a formalized committee and if you bring people in to participate in the same manner as other committee members." Morrison alleges that Lay and others were part of formal working groups under Cheney's task force.

Justice John Paul Stevens dismissed the idea that proof of meetings between Cheney and lobbyists or executives equated to those people being part of his task force.

"They talked to a lot of people, got a lot of advice. Does that make them de facto members of the committee?" Stevens asked. "What does that prove?"

Stevens and Justice David Souter seemed troubled by the idea that granting the Sierra Club and Judicial Watch the right to examine Cheney's documents as part of a trial proceeding equated to a win on the larger issues in the case.

"If you get some discovery and you win your case, what do you get when you win that you will not already have gotten by the discovery?" Souter asked, adding, "Besides a statement saying they were wrong, you win?"

Orfanedes said the information they were seeking at trial could be significantly narrowed by the court. "If we win, we are entitled to basically all the documents of the committee."

The justices are expected to rule in the case by July.