President Obama is set on Tuesday to reassure Americans that his administration is up to the task of coping with the nation's worst environmental crisis, the product of a blown-out BP well that has been gushing crude oil for 57 days deep in the Gulf of Mexico.

In what will be the first televised Oval Office message of his presidency, Obama will not only be addressing his administration's efforts to contain the oil spill but also attempting to reverse the political toll it's taken on his presidency.

With the oil continuing to wash onto beaches and into critical wildlife habitat -- delicate marshlands in particular -- Obama has taken a hit in the polls. And the crisis has taken up much of his time, forcing him to cancel a trip to Asia and Australia while threatening to stall his legislative agenda on such issues as financial overhaul, climate change and immigration reform.

Obama's national speech, expected to be 18 minutes long, sets the stage for his showdown meeting Wednesday at the White House with top executives at British-based, BP, the company that leased the rig that exploded April 20, killing 11 workers and causing the catastrophic spill. It's part of an effort by Obama, who's been seen by some as detached as the oil spill disaster initially unfolded, to convince a frightened Gulf Coast and a skeptical nation that he is in command.

According to senior administration officials, Obama is expected to address the containment strategy -- what is being done to clean up the region, how Gulf Coast residents are being helped and what will be done to ensure a catastrophe like this never happens again.

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House Minority Leader John Boehner, R-Ohio, said Obama shouldn't "exploit this crisis to impose a job-killing national energy tax on struggling families and small businesses."

He also said any escrow fund established should be used to help Gulf Coast victims, "not as a slush fund for trial lawyers or administration officials seeking to paper over their own misguided decisions."

"I sincerely hope that the Obama administration will not try to use a crisis made worse by its own failings to score political points on the backs of Americans living and working on the Gulf Coast," Boehner said in a written statement. "This moment demands a call to action based on our shared interest in stopping this leak, cleaning up this mess, and finding out what went wrong."

Rep. Darrell Issa, R-Calif., urged the president to explain how he plans to replace the Gulf-region jobs that have been suspended due to the six-month moratorium that he imposed.

"With the nation struggling with a prolonged period of joblessness, immediate action is needed by President Obama to get the workers he displaced, by implementing a six-month moratorium on 33 wells, back to work," said Issa, the ranking member on the House Committee on Oversight and Government Reform.

Issa, who is in New Orleans surveying the damage, said he was told that the moratorium is threatening 46,000 jobs if well operations are moved to other parts of the world.

"There is no reason why the politics of this crisis should result in the permanent loss of up to 46,000 American jobs," Issa said. "Advocating a misguided cap-and-tax policy will do little to help address the urgent need to create and retain jobs."

Democrats who were given an advance briefing by the White House on Obama's speech praised the president's remarks.

"It's time to take this tragedy and turn it into an opportunity," Sen. Bill Neslon, D-Fla., said in a written statement. "I congratulate the president on saying we are now going to declare that this nation is getting on the road rapidly to breaking our dependence on oil. We are at a point now, through research and development, that we are going to wean ourselves from petroleum addiction."

The oil gusher a mile deep in the Gulf, which the U.S. government does not have the technology to stop, has forced Obama and the federal government to rely on BP for an eventual fix. That isn't likely to happen until a relief well penetrates the blowout in a couple of months.

In Washington, chief White House spokesman Robert Gibbs said Obama was ready to seize the damage claims process from BP unless the oil giant agrees to set up an "independent entity" to do the job.

Gibbs told television networks that the aim was to compensate individuals and businesses whose livelihoods have been thrown into crisis by the oil spill. Billions of dollars are expected to be involved.

BP's board was in session Monday in London to discuss deferring its second-quarter dividend and putting the money into escrow until the company's liabilities from the spill are known.

The administration had said earlier -- uncertain whether BP would voluntarily establish the damage fund -- that Obama was prepared to force BP to take the step.

The Associated Press contributed to this report.