WASHINGTON (AP) - Reversing a ban on oil drilling off most U.S.

shores, President Barack Obama on Wednesday announced an expansive

new policy that could put new oil and natural gas platforms in

waters along the southern Atlantic coastline, the eastern Gulf of

Mexico and part of Alaska.

Speaking at Andrews air base outside Washington, Obama said,

"This is not a decision that I've made lightly." He addressed the

expected outcry from disappointed environmentalists by saying he

had studied the issue for more than a year and concluded it was the

right call given the nation's voracious thirst for energy and the

need to produce jobs and keep American businesses competitive.

"We're announcing the expansion of offshore oil and gas

exploration but in ways that balance the need to harness domestic

energy resources and the need to protect America's natural

resources," Obama said, standing in front of a Navy F-18 fighter

scheduled to fly on Earth Day with a half-biomass fuel mix.

The president said his decision is part of a broader strategy

that also includes expanding the production of nuclear power and

clean energy sources, to "move us from an economy that runs on

fossil fuels and foreign oil to one that relies more on homegrown

fuels and clean energy."

"The only way this transition will succeed is if it strengthens

our economy in the short term and the long run," the president

said. "To fail to recognize this reality would be a mistake."

Obama made no secret of the fact that one factor in his decision

was attracting Republican support for a sweeping climate change

bill that has languished in Congress. "Drill, baby, drill" was a

mantra of the GOP during the 2008 presidential campaign.

"While our politics has remained entrenched along worn divides,

the ground has shifted beneath our feet," the president said.

"Around the world, countries are seeking an edge in the global

marketplace by investing in new ways of producing and saving

energy."

But Obama also has long been up front about his support for

expanding offshore drilling - as well as other energy sources less

popular with die-hard environmentalists. In his State of the Union

speech, he said he wanted the United States to build a new

generation of nuclear power plans, invest in new coal technologies

and make "tough decisions about opening new offshore areas for oil

and gas development."

The plan modifies a ban that for more than 20 years has limited

drilling along coastal areas other than the Gulf of Mexico. It

allows new oil drilling off Virginia's shoreline and considers it

for a large chunk of the Atlantic seaboard.

Obama's blueprint would allow Interior to go ahead with oil and

gas leases on tracts 50 miles off the coast of Virginia. Those

leases had been approved for development but were held up by a

court challenge and a departmental review.

In addition, the Interior Department has prepared a plan to add

drilling platforms in the eastern Gulf of Mexico if Congress allows

that moratorium to expire. Lawmakers in 2008 allowed a similar

moratorium to expire; at the time President George W. Bush lifted

the ban, which opened the door to Obama's change in policy.

It would allow exploration along the south Atlantic and mid

Atlantic Outer Continental Shelf "to support energy planning" - a

step toward potential leasing.

At the same time, the president also announced that proposed

leases in Alaska's Bristol Bay would be canceled. And the Interior

Department is reversing last year's decision to open up parts of

the Chukchi and Beaufort seas. Instead, scientists would study the

sites to see if they're suitable to future leases.

Obama is allowing an expansion in Alaska's Cook Inlet to go

forward. The plan also would leave in place the moratorium on

drilling off the West Coast.

Under Obama's plan, drilling could take place 125 miles from

Florida's Gulf coastline if lawmakers allow the moratorium to

expire. Drilling already takes place in western and central areas

in the Gulf of Mexico.

The climate change bill has remained elusive.

The president met with lawmakers earlier this month at the White

House about a bill cutting emissions of pollution-causing

greenhouse gases by 17 percent by 2020. The legislation would also

expand domestic oil and gas drilling offshore and provide federal

assistance for constructing nuclear power plants and carbon

sequestration and storage projects at coal-fired utilities.

The president's Wednesday remarks were paired with other energy

proposals that were more likely to find praise from environmental

groups. Some 5,000 hybrid vehicles have been ordered for the

government fleet. And on Thursday, the Environmental Protection

Agency and the Transportation Department are to sign a final rule

that requires increased fuel efficiency standards for new cars.