FACTBOX: Five questions about U.S. offshore oil drilling

(Reuters) - President George W. Bush on Wednesday urged Congress to end a ban on offshore oil drilling in a bid to boost domestic supply amid record-high crude oil and gasoline prices. Here are five questions about offshore oil drilling:

-- What are the politics of the issue? How much of this is electioneering meant to woo voters upset by the price of gas and crude oil?

Republicans and Democrats in the U.S. Congress have identified soaring energy costs as a key issue in the upcoming November elections. Both parties seek to blame each other for record-high gasoline prices averaging more than $4 a gallon nationwide for the first time ever. Republicans have promoted supply-side solutions like drilling offshore and in an Alaska wildlife refuge, while Democrats are mostly pushing demand-side ideas like renewable energy sources.

-- Will the election become a referendum on the issue?

Rising oil and gasoline prices have put energy concerns at the center of the contest between Republican presidential candidate John McCain and presumptive Democratic nominee Barack Obama in November. McCain has embraced offshore drilling in recent days and proposed a plan to build 45 new nuclear power plants by 2030. Obama has criticized McCain's drilling stance, and instead has advocated a plan to slap new taxes on oil company profits.

-- What kind of oil supplies are we talking about?

Bush said opening federal lands off the U.S. coast -- where oil drilling has been banned by both a presidential executive order and a congressional moratorium -- could yield about 18 billion barrels of oil. That would meet current U.S. consumption for about 2 1/2 years, but it would likely take a decade or more to find the oil and produce it. The prospect of more energy supply down the road could calm nervous traders who see a looming global oil crunch, but any actual supply would be years away even if Congress acted quickly.

-- What is the real threat to the environment?

Environmental groups warn that offshore drilling opens the door to oil spills and litter that could mar pristine beaches in Florida and California. But oil companies claim they have improved their drilling technology to the point that the risk of offshore oil spills is nearly nil.

-- Which companies stand to benefit?

U.S. oil companies like Exxon Mobil, Chevron Corp and ConocoPhillips have consistently pressed for more access to U.S. drilling acreage. International oil companies are facing dwindling prospects abroad as countries like Venezuela and Russia tighten access to prime drilling property and demand a higher take of the profits.

(Reporting by Chris Baltimore, editing by Matthew Lewis)