By Amy Harder and Beth Reinhard, The Wall Street Journal.

Shortly after a conservative website on Wednesday posted 2008 footage of Sen. Marco Rubio backing a cap-and-trade program to combat climate change, his campaign roared back with a counterattack that included an entire web page aimed at debunking the video.

Mr. Rubio’s muscular response revealed how toxic the issue of climate change has become in the Republican Party under President Barack Obama, who has sought to make reducing carbon emissions to alleviate global warming one of his signature accomplishments.

As speaker of the Florida House, Mr. Rubio did vote for a 2008 bill authorizing the state to come up with rules for a cap-and-trade plan, though he raised questions about its cost and effectiveness. A press release from the House Majority Office at the time described the bill as a “responsible response to concerns about global climate change.”