GOP seeking a single voice on climate issue Senate Republicans began an unusual closed-door debate on climate change Wednesday that may portend a shift toward the position of the party’s presumptive presidential nominee, Sen. John McCain (Ariz.). The meeting of the conference launched GOP efforts to find a common position on global warming, an issue on which Republicans have been sharply divided. The issue has taken on a greater urgency within Republican circles now that all the major presidential candidates, including McCain, support mandatory controls of greenhouse gases. This represents a sharp break with the Bush administration, which has fought such proposals vigorously. Wednesday’s meeting did not produce a consensus and may have ultimately helped solidify GOP opposition to the leading proposal on climate change. Still, several Republican senators said it marked a shift in the debate. Instead of arguing over the science underpinning global warming, the meeting focused almost exclusively on the impact a mandatory system to control greenhouse gases would have on the economy and the environment....