After spending the entirety of his campaign refraining from engaging in political attacks against his opponents, Democratic presidential candidate Bernie Sanders responded to attacks made by a pro-Clinton super PAC against the Vermont senator.

Representatives of Correct the Record, the pro-Clinton super PAC, attacked Sanders while speaking to a reporter about the senator. They, according to an email from Sanders to his supporters, “suggested I’d be friendly with Middle East terrorist organizations, and even tried to link me to a dead communist leader [Hugo Chavez].”

It was the kind of onslaught I expected to see from the Koch Brothers or Sheldon Adelson, and it’s the second time a billionaire Super PAC has tried to stop the momentum of the political revolution we’re building together,” Sanders added.

Part of Sanders’ response included him linking Clinton to a few political snafus of her own. He noted Clinton’s connection to wealthy donors, “dirty tactics,” and the infamous Koch brothers, who run a multi-million dollar political network for conservatives.

Michael Briggs, Sanders’ spokesperson, said the Clinton super PAC was “distorting the record.” The campaign argues that the attack is rooted in anxiety that Clinton is losing support in Iowa and New Hampshire, both are key states.  

“It is disappointing that Secretary Clinton’s super PAC is spreading disinformation about Bernie,” Briggs said. “This is exactly the kind of politics that Bernie is trying to change. To equate bringing home heating oil to low-income Vermonters with support for the Chavez government is dishonest.”

Clinton is on the ropes, and her supporters are resorting to filthy, political mud-slinging out of desperation. The PAC’s leader, David Brock, has reportedly sent trackers after Sanders and fellow-Democratic candidate Martin O’Malley.

For more on this story, visit the Huffington Post and The Hill.

Watch Thom Hartmann’s take on this issue: