WASHINGTON - The General Accounting Office will sue the White House for access to documents from President Bush's energy task force, the agency said in a letter yesterday to congressional leaders.

The GAO's statement that it will take the White House to court sets up a political battle over executive privilege. Bush on Monday flatly refused to hand over the documents, saying to do so would encroach on his ability to freely seek outside views.

The GAO and congressional Democrats want to force Vice President Dick Cheney, who ran the task force, to turn over documents on meetings last year with business executives in crafting a national energy policy.

Some of the participants in the meetings were officials from the now-collapsed Enron Corp., a Houston-based energy trader with deep ties to Bush.

Comptroller General David Walker, head of Congress' investigative arm, said if GAO backs down it would "significantly undercut" its investigative ability in the future.

"We would have strongly preferred to avoid litigation in connection with this matter," Walker wrote. "But given the request by the four Senate committee chairmen and subcommittee chairmen, our rights to this information and the important principal and precedents involved, GAO will take the steps necessary to file suit in United States District Court."

The letter was provided to The Associated Press by congressional sources.

Walker did not say in the letter when the lawsuit will be filed.

It would be the first time in the GAO's 80-year existence that it sued the executive branch. The lawsuit would be filed in the U.S. District Court in Washington.

The White House said it had not received notification of the GAO lawsuit. "The president will stand on principle and for the right of presidents and this president to receive candid advice without it being turned into a news release," said White House spokesman Ari Fleischer.

White House officials, fearing political fallout from the legal action, scrambled to raise questions about the GAO's actions.

GAO officials also were calling congressional leaders yesterday to tell them of the decision.

The White House said Kenneth Lay, then- chairman of Enron, gave Cheney a three-page document in April arguing for federal authorities to refrain from imposing price caps or other measures sought by California officials to stabilize electricity prices. Lay was one of Bush's biggest political supporters.

"Events in California and in other parts of the country demonstrated that the benefits of competition have yet to be realized and have not reached consumers," the memo said.

Cheney spokeswoman Mary Matalin dismissed the significance of the memo, first reported by the San Francisco Chronicle. Nine of Lay's 11 suggestions were not included in the White House energy plan - and the two that made the report were noncontroversial, she said.

On Tuesday, an energy consultant suggested to the Senate Energy and Natural Resources Committee that Enron may have been using largely secret trades to manipulate energy markets.

Robert McCullough, a consultant whose clients include several Northwest utilities, testified that in the week after Enron announced its bankruptcy, the "forward price" of electricity in the West fell sharply. Enron had been a key trader in this market, which is used as a hedge against future power price changes and is unregulated.

"That certainly raises the question about whether Enron was manipulating the West Coast market" by keeping prices artificially high, Sen. Ron Wyden, D-Ore., said in response to the consultant's testimony.

McCullough said "the clear implication is that Enron may have been using its market dominance to set forward prices."

Other energy experts said other reasons may have been behind the price decline. Lawrence Makovich, a power industry expert at Cambridge Energy Research Associates, said it would be impossible to determine simply from the decline in price whether prices were manipulated.

The Federal Energy Regulatory Commission told the Senate panel it would investigate Enron's influence on wholesale electricity prices.

In resisting the GAO's demands, Cheney insists that providing the list of industry executives would harm his ability to receive advice in the future and that the congressional investigators are overstepping their bounds.

Any GAO lawsuit would be highly controversial on Capitol Hill. The agency's investigation began after Democrats on April 19 requested that GAO investigate the conduct, operations and funding of the Cheney energy task force.