The proposal to expand drilling to those areas, unveiled just three weeks before the BP accident, was part of a political plan to encourage more domestic oil production in exchange for Congressional action to limit carbon dioxide emissions that are contributing to global warming.

The eastern gulf and the Atlantic Seaboard had been off limits to oil companies for years because of Congressional opposition, but lawmakers in Atlantic coast states have been pushing for offshore oil activity to reduce foreign imports and to generate tax and royalty revenue.

Ultimately, Wednesday’s announcement was an admission that the Interior Department erred in deciding last spring to open up vast new areas offshore to drilling without adequate safeguards. And politically, the plan brought the Obama administration nothing.

The administration’s package fell apart as a result of the oil spill and the Senate’s refusal to take up comprehensive legislation on energy and climate change. Prospects for such legislation are even dimmer now after the Republican takeover of the House.

Oil company executives said that while they had been eager to begin drilling in the eastern gulf and along the Atlantic coast, they could not estimate how much they would have been willing to invest there. That would require exploration, which will now be deferred for years to come, although federal geological officials could potentially carry out acoustic tests to map oil reserves.

The government estimates that the eastern gulf contains 3.7 billion barrels of oil and 21.5 trillion cubic feet of gas, while the Atlantic coast has 3.8 billion barrels of oil and 37 trillion cubic feet of gas. Taken together, that is roughly comparable to Norway’s proven oil reserves and Canada’s proven gas reserves.

The expansion of offshore drilling announced in March only partly opened those waters; but it still would have made available enough oil to fuel more than 2.4 million cars and gas to heat 8 million households for 60 years.