How Green is the Bay State?

Today, seven Northeastern states are expected to sign what they call a landmark agreement to limit greenhouse gas emissions. Massachusetts led the push for the regional plan, but will not sign the final deal. The states that will do so say they made changes designed to address Governor Mitt Romney's concerns, but he pulled out of the pact last week.

Is the governor's decision based on politics or policy? And what's the effect on Massachusetts' reputation as an environmental leader? Martha Bebinger examines these questions.