Under fire from Republicans, top Democratic politicians in the United States are considering lifting a ban on new offshore oil drilling.

    The issue is now at the forefront of the presidential election, as Republican candidate John McCain has made allowing new drilling one of the centrepieces of his campaign, claiming that it will help drive down petrol prices.

    Democrats have hitherto said new drilling would do little to relieve consumer pain at the pump, accusing Republicans of misleading the public
and being a pawn of big oil companies. Yet signs are emerging that they are easing their opposition to the comprehensive ban.

    Last week House Speaker Nancy Pelosi said she would consider allowing a congressional vote on the issue if drilling was part of a wider energy plan that also focused on promoting alternative energy sources. Pelosi told a television interviewer that she would consider a vote, but 'it has to be part of something that says we want to bring immediate relief to the public, and not just a hoax'.

    More than 30 Democrats have signed up to sponsors legislation that could pave the way for fresh drilling off America's coasts. Democratic presidential candidate Barack Obama has also moderated his stance, moving from staunch opposition to suggesting that new drilling could be part of a new energy strategy. That shift led to accusations from some of his supporters that he had flip-flopped.

    A group of politicians from both parties, dubbed the 'Gang of 10', has proposed a mixed strategy of new drilling and alternative energy, which could gather wide support.

    Yet plans for any fresh off-shore drilling have outraged environmentalists. They believe it will take years to develop any oil reserves and that the move represents nothing more than a bonanza for an oil industry that already gets huge tax breaks. They also believe it will eventually pave the way for drilling in ecologically sensitive areas, such as parts of Alaska.

    But the issue has become a problem for the Democrats after McCain enthusiastically embraced the idea. In the unusual setting of a massive biker rally in the small town of Sturis, South Dakota, the Republican recently told a cheering crowd: 'We're going to drill here and we're going to drill now!' It is a line that has since been repeated on the campaign trail and has struck a chord with those parts of the American public for whom high petrol prices are the key concern. It certainly threw Democrats off-balance, as they tried to push a more balanced energy policy with longer-term aims of reducing oil use.

    But energy policy has rapidly become the hot topic of the election, overtaking even Iraq or Georgia. In a country whose cultural and economic life is dominated by the car, there are no more passionate debates than over the doubling of petrol prices in the past couple of years.

    It has offered hard-nosed Republican campaigners an issue to rally around and a stick with which to beat an Obama campaign that has started to make rare missteps. In one recent incident Obama mentioned that, if Americans kept their tyres inflated correctly, it would save petrol consumption and reduce the need for drilling. The comment was factually true, but was seized on by Republicans, who carried out numerous stunts, such as delivering tyre gauges to reporters on the campaign trail. It became a powerful theme on conservative talk radio, where hosts lampooned Obama and accused him of putting tyre pressure at the forefront of his energy policy.

    In fact, the energy debate has enlivened a Republican party that has recently seemed moribund beside the huge and well-run Obama operation. It has allowed the party to attack the Democrats and set the agenda of the recent political debate, giving Republican activists a sense of hope.

    'This is a narrow race. Obama has a solid edge, but it is still close,' said Professor Shawn Bowler, a political scientist at the University of California at Riverside. The polls are bearing that out. As the party convention season looms, the RCP national average of polls has Obama ahead by just three points. In the battleground states the picture is mixed, with McCain ahead in Missouri, Virginia and Florida, and Obama leading in Ohio, Michigan and Colorado.