MarketWatch: The 2008 presidential election will mean major changes in United States energy policy. William F. Weld, partner advising on government strategies and energy policy for the law firm of McDermott Will & Emery and a former two-term governor of Massachusetts, believes that the biggest impact will come on two issues: climate change (global warming) and dependence on foreign oil. Mr. Weld says both Senator John McCain and Senator Barack Obama have taken strong but different stands on these issues, …