After what was widely recognized as a tough week, Barack Obama's campaign is trying to get back on the offensive, releasing a negative television ad, hosting a morning conference call, and now, in an energy speech, sharply attacking John McCain.

From the prepared comments:

"You won’t hear me say this too often, but I couldn’t agree more with the explanation that Senator McCain offered a few weeks ago. He said, ‘Our dangerous dependence on foreign oil has been thirty years in the making, and was caused by the failure of politicians in Washington to think long-term about the future of the country.  read more »

The ramp-up to Mike Bloomberg's big Earth Day roll-out continues.

In radio address this morning, the mayor managed a trifecta of proposals that many energy experts will love but which, it's probably fair to say, most vote-seeking, non-billionaire politicians would hesitate to touch with a ten-foot pole.

He pushed for "raising the gasoline tax," and compelling car manufacturers to make more energy-efficient cars.

As for new sources of energy, "the only rational answer," Bloomberg said, is to look towards nuclear power.

Bloomberg also dismissed the idea of relying to heavily on ethanol. (Hello, Iowa!)

More details later.