McClatchy Newspapers: Three weeks after oil began spewing into the Gulf of Mexico , an angry President Barack Obama vowed Friday to end the cozy relationship between the oil industry and government regulators and impose tough new environmental safeguards on offshore drilling. Environmentalists, however, voiced skepticism that the president’s denunciation of the three companies implicated in the spill is a watershed in the long relationship between federal regulators and the oil industry, which has written …