Massachusetts v. EPA (2007)

1) Link to the Actual Opinion
Read the U.S. Reports opinion (PDF)

2) Summary of the Opinion
A group of states, led by Massachusetts, sued the EPA for refusing to regulate greenhouse gases from motor vehicles under the Clean Air Act. The Supreme Court held that greenhouse gases are air pollutants under the Act and that the EPA has authority—and responsibility—to regulate them if they endanger public health or welfare.