After the political tidal wave of 1994 swept conservatives into control of Congress, Republicans doggedly tried -- and repeatedly failed -- to repeal a Depression-era law that requires federal contractors to pay workers the prevailing wages in their communities. Eleven days after the deluge of Hurricane Katrina, President Bush banished the requirement, at least temporarily, with the stroke of his pen.

The president's suspension of the Davis-Bacon rules on wages is one example of the many avenues the disaster has opened for the administration and lawmakers of both political parties to incorporate long-held -- and normally polarizing -- policy goals into the huge federal aid racing to the Gulf Coast.

Federal procurement agents are using the outpouring of federal largess -- $62 billion so far -- to ease quotas for minority and small businesses in government contracts. Republicans are trying to revive, for schoolchildren displaced in the disaster, their frustrated efforts to create government vouchers for private schools. Democrats, meanwhile, are trying to use the emergency to expand Medicaid health insurance for low-income families and to reverse some tax cuts Bush pushed through Congress.

Taken together, the efforts have the potential to alter domestic policy in a way that parallels the reshaping of realms such as military intervention and civil liberties after the Sept. 11, 2001, terrorist attacks.

With a weakened president, a Republican Party eager to demonstrate concern for the disadvantaged and a Democratic Party accused of obstructionism, the horse-trading will only intensify, said Paul C. Light, who specializes in governmental organization at New York University. "If you're seeing it now, when Congress was on vacation and hadn't had much time to think about it, imagine what you'll see in six weeks when they've had time to sit down and work on it," Light said.

Already, Katrina's wind and water have ushered in two significant changes, a suspension of wage supports and a relaxation of government contracting rules.

The 1931 Davis-Bacon Act was passed, in part, by segregationists hoping to stem the tide of blacks into the cities, but since then the law has been cherished by labor unions -- and despised by many Republicans. President George H.W. Bush suspended the wage rules in late 1992 after Hurricane Andrew, only to see them reinstated weeks later by incoming President Bill Clinton. Republicans tried to repeal it outright in the budget battles of 1995. As recently as last year, Rep. Marilyn Musgrave (R-Colo.) tried again.

On Wednesday, when White House budget director Joshua B. Bolten briefed House Republicans on the president's latest supplemental spending request, conservative lawmakers urged him to lift the wage rules. Bush did so the following day, through an executive order that applies to all construction projects -- related to the storm or not -- in Louisiana, hard-hit sections of Mississippi and Alabama, and South Florida's urban counties of Miami-Dade and Broward. "Lots of people in Louisiana are willing to go to work tomorrow, and the market will set the wage," said Rep. Tom Feeney (R-Fla.).

In another gain for the administration, a $51.8 billion relief bill that Congress passed on Thursday included a significant change to federal contracting regulations. Holders of government-issued credit cards will be allowed to spend up to $250,000 on Katrina-related contracts and purchases, without requiring them to seek competitive bids or to patronize small businesses or companies owned by minorities and women. Before Thursday, only purchases of up to $2,500 in normal circumstances or $15,000 in emergencies were exempt.

"The provision in the supplemental is intended to cut red tape for contracts less than $250,000 and get food, water and housing to the victims as soon as possible. We are certain that small businesses -- particularly ones located in the affected region -- will play a critical role in the disaster relief effort," said David Safavian, administrator of the White House's Office of Federal Procurement Policy.

While acknowledging that the White House's main goal is to accelerate the flow of aid, Democratic aides said the changes to procurement rules had been sought by government procurement agents for years without success, until now.

Sensing an opening, Republican leaders have also begun to lobby the White House to resume the drive for vouchers that would allow government money to be used at private and parochial schools, a battle that Republicans waged and lost during the debate over the No Child Left Behind education law of 2001. "If we make the decision that federal money will follow the child, we should make it a voucher. That's a Republican principle," said Rep. Jeff Flake (R-Ariz.).

Similarly, Republican leaders are seeking a change in a law that would allow the Federal Emergency Management Agency to give money directly to religious groups that are helping Katrina's survivors, an extension of the administration's long-standing goal of enlarging the role of faith-based organizations in providing social services. "The important thing is to empower and encourage anyone who is willing and able to help to administer emergency help," said Kevin Madden, spokesman for House Majority Leader Tom DeLay (R-Tex.).

Sensing an opening to pursue their own agenda, Democrats are drafting proposals that advance their goals. "Oh, God, everybody in the world is thinking about their little pet project right now," said a senior House Democratic aide.

Already, House and Senate Democrats, who have complained for years that the government should take larger steps to provide health coverage to the escalating number of Americans who are uninsured, have introduced legislation that would temporarily broaden the scope of Medicaid.

The bills would redefine the program, usually restricted to low-income people, so that survivors of Katrina could sign up, regardless of income. In addition, the Democrats would allow into Medicaid single men and couples without children, people that usually are not eligible. And they would pay for the extra insurance entirely with federal money, no matter how high the cost runs, eliminating the usual arrangement that requires states to shoulder a big share of Medicaid's cost.

The Senate version, which would last six months, would cost $6 billion to $8 billion, while the House bill would last a year.

Rep. John D. Dingell (Mich.), the ranking Democrat on the House Energy and Commerce Committee, said the scale of the disaster warrants such changes. "Would you want to be the fellow that tells a single man or childless couple that we are going to take care of their next-door neighbor and we are not going to take care of them when both are wiped out in the flood? I don't want to be the guy that does that."

Dingell said the main motive behind the legislation "is to help people who are desperate" and to give states an incentive to help survivors with health care "without going broke," not to use the disaster as a chance to expand the program.

Senate Democrats have also introduced legislation that would expand the use of federal rent vouchers for Katrina's victims, countering the administration's efforts to diminish reliance on the nation's main rent-subsidy program, known as Section 8. The Democratic proposal would create a new program within the Department of Housing and Urban Development that would resemble Section 8, but with important differences: People who have lost homes would qualify for vouchers no matter how much money they earn, subsidies would be larger than the government usually allows, and tenants would not have to chip in until they find a job.

And Democrats are preparing to do something they have been unable to do for five years: Thwart a Republican tax cut. Democrats helped spur Senate Republican leaders to postpone a showdown last week on the permanent repeal of the estate tax. And they stirred enough political concern to delay, by at least a month, the planned passage of $35 billion in entitlement-spending cuts and $70 billion in tax cuts.

President Bush signed the first bill providing relief aid for victims of Hurricane Katrina on Sept. 2. He signed a second one on Thursday.