It's becoming increasingly clear that the Republican race is down to McCain and Romney, and they are rapidly escalating their attacks on one another.

Romney is now using McCain's climate legislation against him:

In a new line of attack, Romney then tore into the McCain-Lieberman Climate Stewardship Act.

"Instead of seeing if there's a way of stimulating the economy, McCain-Lieberman would depress the economy," Romney said.

"His plan calls for a new financial burden to be placed on people who are purchasing gasoline, or for that matter, natural gas to heat their homes or to cook in their homes. The energy information agency has said that his plan would cost America 300,000 jobs. In addition, people would pay, they estimate, approximately 50 cents per gallon more for gasoline and 20 percent more for their gas utility bill. That would depress the economy just at a time when we’re trying to stimulate the economy."

The EIA analysis Romney's referring to is here.

Romney may get some distance out of this economic pandering in a Republican primary -- it won him Michigan -- but it could hurt him badly in the general. Not only is the public on board with mandatory climate caps, but so are several of the most popular and appealing Republicans outside of D.C., most notably Cali. governor Arnold Schwarzenegger and Fla. governor Charlie Crist (who endorsed McCain the other day).

Cali will go Dem either way, obviously, but opposition -- or even tepid support -- from Crist could sway Florida, which is a big deal.