The campaign of Democratic congressional candidate Sean Eldridge is knocking Rep. Chris Gibson for signing on to a “no climate tax” pledge that is supported by Americans For Prosperity, a group founded by industrialists David and Charles Koch.

Gibson on Capital Tonight Thursday knocked Eldridge’s stance on energy taxes, saying it’s more evidence that he’s out of step with the congressional district.

“My opponent criticizes me for opposing energy taxes, he shows he’s not from here,” Gibson said.

Eldridge’s campaign, though, says this line is a reference to the AFP pledge.

“Politician Chris Gibson claims in an election year that he is in line with his constituents on the environment, but the Real Chris Gibson signed the Koch Brothers pledge and has an 33 percent lifetime rating from the League of Conservation Voters,” said spokesman Morgan Hook. “If Chris Gibson is so proud of his record in Washington – as he says – then why doesn’t he just come clean to New Yorkers about his commitment to the Koch brothers to take no meaningful action on climate change? Voters in NY-19 know where Sean Eldridge stands on the issues, including his opposition to hydro-fracking and his efforts as a former board member of Scenic Hudson to protect our environment and prepare communities in the Hudson Valley for climate change and sea level rise.”

The Koch brothers and their political activities, of course, remain useful foils for Democratic candidates around the country, Eldridge’s campaign not being an exception.