Adopting a central organizing principle means embarking on an all-out effort to use every policy and program, every law and institution, to halt the destruction of the environment.

The global environment crisis is, as we say in Tennessee, real as rain, and I cannot stand the thought of leaving my children with a degraded earth and a diminished future.

Eventually we'll use a CO2 tax offset by a reduction in taxes elsewhere alongside a cap-and-trade plan, but the degree of difficulty associated with a CO2 tax far exceeds that with a cap-and-trade plan. We're seeing it's hard to get a cap-and-trade plan and it's much easier to use as a basis for a global agreement than a CO2 tax.

Local and state governments have outrun the federal government. The EPA has served notice that it will enact a rule requiring CO2 reductions by major emitters in the absence of major legislation. But it's a blunt instrument that is a little more difficult to use than a legislative remedy.

I've been dreaming of this moment since I was a kid growing up in Tennessee: that one day, I'd have the chance to come here to Madison Square Garden and be the warm-up act for Elvis.

I don't really consider this a political issue, I consider it to be a moral issue.

The presidency is more than a popularity contest.