Shale gas fuels change in US swing states ©Reuters A worker performs a routine check at a natural gas appraisal well in China The shale revolution is spreading into eastern Ohio, bringing with it the possibility of reviving an economy that has faltered since industrial jobs left the region. But along with that promise, the shale wave is also bringing with it an increasingly intense brand of election-year politics. The Utica shale stretching from western Pennsylvania into Ohio is thought to be rich in oil and natural gas liquids, such as ethane, and is attracting billions of dollars in investment from US and foreign companies. Although large-scale production is not expected to start until next year, the industry's potential is already causing excitement in Youngstown, which has struggled for two decades to overcome the loss of its heavy industrial base. Paul Sracic, at Youngstown State University, says the intense focus on shale development has the potential to make energy a big issue in what is the country's key swing state. "Blue-collar voters were never that sold on environmental issues, and if some Democrats come across as not keen on economic development, it could lose them support here in Ohio," he said. Republicans, from Mitt Romney, the party's presidential candidate, to the congressional leadership, have made Barack Obama's alleged stifling of the energy industry a centrepiece of their campaigns this year. Mr Obama says the claim is nonsense - domestic energy production is at its highest since 1998 and employment in the sector has risen 17 per cent during his three-and-a-half years in the White House. But Republicans and the cashed-up campaign groups that back them in the presidential and congressional elections say Mr Obama's delay of the Keystone XL pipeline from Canada is symbolic of his reticence to let the industry reach its full potential. In April, when petrol prices were rising, a wave of negative ads costing tens of millions of dollars from various campaign groups such as Americans for Prosperity and American Energy Alliance, both underwritten by energy interests, were broadcast attacking Mr Obama. The ads target Mr Obama for his refusal to approve the pipeline, restricting coal mining and using public funds to bankroll Solyndra, the solar energy company in California that later went bankrupt. Mr Romney has said he will approve the Keystone XL pipeline as soon as he wins office and curb the powers of the Environmental Protection Agency. "Big oil and big energy companies are doing everything they can to elect Mitt Romney because he will undo public health safeguards that cost them money," said Daniel Weis, of the Center for American Progress Action Fund. For an investment of tens of millions of dollars, they can save billions. The American Petroleum Institute, the industry lobby in Washington, is launching its own campaign this week to put energy at the centre of the election, although it does not directly advocate a vote for either candidate. Most of the 15 states where the API has been holding its meetings will be important battlegrounds for the presidential election, and in three of them - Ohio, Colorado and Pennsylvania - oil and gas are playing an increasingly important role in their economies. Tony Paglia, of the Youngstown/Warren regional Chamber of Commerce in Ohio, says: "There's going to be a lot of money poured into the area, which we haven't seen for many, many years." Already, the boom in gas production in neighbouring Pennsylvania's Marcellus Shale has created an estimated 2,000 jobs in the past 18 months in businesses providing services and equipment such as steel pipes. Vallourec of France has invested $650m to open a new steel mill in Youngstown. "We haven't seen the Republicans using it as a wedge issue, but I can see it becoming one," Professor Sracic said. Ohio is going to be very, very close and little things can mean a lot.