In the last two days of the presidential campaign, coal has made a comeback. Republican Sarah Palin toured southeast Ohio saying Democratic candidate Barack Obama wants to "bankrupt" the coal industry.   Palin's charges stem from statements Obama made to the editorial board of the San Francisco Chronicle in January. Obama was talking about his energy plan and his support of an "aggressive" cap-and-trade policy aimed at limiting greenhouse gas emissions. Obama said: "So if somebody wants to build a coal-powered plant, they can. It's just that it will bankrupt them, because they're going to be charged a huge sum for all that greenhouse gas that's being emitted," he said. In the same interview, the senator said that "if technology allows us to use coal in a clean way, we should pursue it."Palin contended a tape of the interview had been kept secret by the newspaper. The tape had actually been on the newspaper's website since January. "The point Obama is making is that we need to transition from coal-burning power plants built with old technology to plants built with advanced technologies — and that is exactly the action that will be incentivized under a cap-and-trade program," the campaign said in a statement.