With fellow Republicans set to run Congress and a federal court upholding his right to secrecy, President Bush over the next two years will be protected from potentially embarrassing congressional investigations into his administration, especially its relationship with big corporate donors, government officials say.

Starting next month, Senate Governmental Affairs Committee Chairman Joseph I. Lieberman (Conn.) and other top Senate Democrats will lose their chairmanships and much of their power to initiate investigations of the Bush administration, subpoena key officials and hold public hearings on possible wrongdoing. As a result, Bush will likely escape close congressional scrutiny of the role his biggest corporate contributors play in shaping administration policy on environment, energy and other pro-business issues.

A Republican-appointed judge last week provided the Bush administration another layer of protection from congressional scrutiny and dealt a blow to a campaign by Democrats to reveal how energy companies helped devise the administration's comprehensive energy plan last year. The judge, John D. Bates, threw out a case brought by the head of the General Accounting Office, the investigative and auditing arm of Congress, that would have required Vice President Cheney's energy task force to release secret records of White House meetings with industry officials. Now, Bush is in a strong position to keep secret potentially embarrassing details of conversations between his staff and energy industry officials trying to influence their decisions.

More broadly, the court ruling will have a chilling effect on efforts by Democrats to use the GAO to monitor the executive branch. If the courts refuse to compel White House officials to comply with GAO requests for information, they'll have little reason to cooperate, Democrats say.

Unless the ruling is reversed, "Bush and Cheney can operate in complete secrecy with no oversight by Congress," says Rep. Henry A. Waxman (Calif.), the top Democrat on the House Government Reform Committee.

In another move that could help shield Bush from scrutiny, Government Reform Chairman Dan Burton (R-Ind.), who irritated some Republicans with his willingness to challenge the Bush White House over FBI abuses and its penchant for secrecy, will be stepping down. While Democrats feel that Burton gave Bush a free pass, especially compared with his hounding of President Bill Clinton during the 1990s, GOP leaders want Burton's successor, who has yet to be named, to focus less on potential wrongdoing in the administration and more on downsizing government, GOP leadership aides say.

"Under unified party control," says Paul C. Light of the Brookings Institution, "there tends to be a lessening of the police patrolling that has had some significant breakthroughs" in rooting out malfeasance. "That's the nature of the beast." Light, a former congressional aide specializing in government oversight, is an expert on the federal bureaucracy.

A weaker checks and balances system could strengthen Bush's hand heading into his expected campaign for reelection in 2004. Polls show Bush is vulnerable to attacks that his policies are influenced too heavily by corporations and big donors. The fewer investigations and public hearings on this matter, the better, as far as Republicans are concerned.

A senior GOP leadership aide said House Republicans plan to wield their oversight power by looking into ways to privatize and downsize government programs. This will keep the focus on ideas backed by the White House and congressional leaders, not on money and politics, the aide said.

This isn't how the framers of the Constitution envisioned the systems of checks and balances, critics say. The framers wanted Congress to keep a close eye on the inner workings of the executive branch to guard against abuse and wrongdoing. Congress does this through general oversight, hearings at which White House and administration officials are called to testify publicly, and full-blown investigations. Yet, when the president's party controls the House and Senate, he usually gets friendly treatment.

To be sure, the Senate has its share of maverick Republicans. Incoming Commerce, Science and Transportation Committee Chairman John McCain (Ariz.) and Banking, Housing and Urban Affairs Committee Chairman Richard C. Shelby (Ala.) have histories of holding the president's feet to the fire.

But Democrats worry potential transgressions will go unnoticed. The oversight process -- while sometimes abused by partisans to embarrass presidents -- has uncovered abuses of power ranging from campaign finance scandals in the Clinton administration to defense procurement scams in the 1980s. The Bush administration, led by Cheney, has waged a war to reverse what it sees as an erosion of the power of the presidency over the past 30 years. Starting in the 1970s, Cheney contends, Congress responded to Watergate and Vietnam by passing laws to provide the legislative branch greater authority over the president. Since then, Congress has been increasingly aggressive about demanding everything from e-mail messages to secret documents from the White House, with some success.

Bush has pushed back. He refused to disclose details to the GAO and lawmakers about Cheney's task force on new energy laws, taking its fight to the courts. He refused to allow homeland security director Tom Ridge to testify before Congress about anti-terrorism planning inside the White House.

Most recently, Bush blocked a commission to investigate the terrorist attacks on Sept. 11, 2001, favored by lawmakers. In the end, Bush forced a compromise allowing him to appoint the head of a new bipartisan commission, Henry A. Kissinger, a Republican. Kissinger resigned the post Friday.

After helping Republicans win back the Senate and expand their House majority, Bush is in a strong position to beat back any inquiries in the 108th Congress.

It's unlikely incoming Governmental Affairs Chairman Susan Collins (R-Maine) will pursue investigations of Bush's ties to energy companies and other corporations, as Lieberman was planning to do, Republican aides say. In a statement, Collins did not disclose her plans but suggested she won't back down from pressing the White House for information. "I believe that any administration should provide documents and information that Congress legitimately needs to carry out its investigative responsibilities," Collins said.