Setting up a cap-and-trade system for greenhouse-gas emissions would be one of Barack Obama’s top economic priorities if he were elected president, right up there with a new health-care system, The Wall Street Journal reports. As part of an effort to cut emissions 80 percent below 1990 levels by 2050, Obama would auction off pollution permits, raising more than $100 billion a year that could be spent on clean energy, efficiency, and green-jobs programs, among other things. If Congress didn’t want to play along, an Obama administration “wouldn’t hesitate to use Clean Air Act authorization to regulate” carbon dioxide emissions under the authority of the U.S. EPA, says Obama energy advisor Elgie Holstein. The Supreme Court ruled last year that the EPA has the authority to do just that, but the Bush administration has refused to exercise that power. Obama seems less committed to his proposals to impose a “windfall-profits” tax on oil companies and tap the strategic petroleum reserve; aides say these plans could be dropped if the price of oil declines or worries about energy subside.