To underscore how seriously he is taking the BP oil spill in the Gulf of Mexico, President Barack Obama has chosen to make his nationwide address on the environmental disaster his first speech from the Oval Office, a setting presidents typically reserve for the gravest occasions – President George W. Bush spoke from there after the September 11 attacks, President Bill Clinton announced air strikes on Iraq, and President Ronald Reagan chose the Oval to talk about the explosion of the space shuttle Challenger.

Administration officials said Obama will lay out how to deal with the oil that has leaked so far and what must be done to clean up and restore the Gulf, talk about what is being done for those who have lost jobs and business because of the disaster and discuss changing U.S. energy policy to reduce dependence on oil and fossil fuel. 

As he grapples with the spill, Obama has been pushing Congress to pass a new law that would fight climate change and ramp up production of renewable fuels, but the measure faces an uncertain future in the Senate, where Republican leaders are sternly denouncing any effort to link provisions of the energy bill with the Gulf disaster.

“Tonight’s speech comes at an inflection point in the oil spill,” aides said, using the expression for a point marking the beginning of a significant change on a curve, or a chart.

“President Obama understands the challenges and has clear plans to meet them,” they said.