U.S. News and World Report: When Rep. Henry Waxman of California and Rep. Ed Markey of Massachusetts released a draft of a much-anticipated global warming bill last week, it effectively marked the start of this year’s debate over regulating greenhouse gas emissions. But even with a Democratic majority in Congress and a sympathetic Obama administration, it’s going to be a long, tough fight. The debate centers on a proposal to create a cap-and-trade program, which, if passed, would set national limits on …