09/14/2012 06:16 pm ET Updated Dec 06, 2017

David Gill, Single-Payer Advocate, Targeted By American Action Network

The conservative American Action Network (AAN) is out with its first ad of the general election, going after Democratic congressional candidate David Gill for advocating a single-payer health care program.

"Gill wants a single-payer health plan more radical than Obamacare. Gill would eliminate Medicare, put bureaucrats in charge of health care decisions and add a new 2 percent tax to pay for it, costing families $1,000 a year to pay for it," the ad's narrator says.

Gill has been critical of insurance companies' roles in passing health care reform and is an advocate for a single-payer system. The insurance industry opposes such a plan because the federal government would pay hospitals and doctors directly for their services.

But while the AAN ad goes after Gill on the issue of Medicare, the health plan for senior citizens is actually a single-payer system run by the government. Advocates for single-payer often say they essentially want "Medicare for all."

The ad comes a few months after it was revealed that AAN received a more than $3 million donation from Aetna in 2011. While the CEO of the health insurance giant praised Obamacare as recently as February, its donation to AAN shows that it was not always so supportive of the administration's efforts. Aetna also gave more than $4 million to the U.S. Chamber of Commerce, which also wants Obamacare repealed.

AAN is strongly opposed to the Affordable Care Act and has been pushing for its repeal, even before the Aetna donation.

"I wonder how much influence Aetna has on exactly which lawmakers AAN and the Chamber target?" asked Melanie Sloan, head of the watchdog group Citizens for Responsibility and Ethics in Washington, which discovered the donations that Aetna had inadvertently disclosed. "Just because Aetna isn't telling the public what it's up to, doesn't mean the company is hiding its political activities from everyone. I'm sure Aetna is expecting lawmakers to express their gratitude with legislative favors. Just like these grateful lawmakers, Americans should know what Aetna is really doing with their insurance premiums."

When asked whether the Aetna donation had anything to do with the most recent ad, AAN spokesman Dan Congdon replied, "I'm not going to entertain questions this ridiculous."

Aetna did not respond to a request for comment on the anti-Gill ad.

Gill is running for the seat in Illinois' newly drawn 13th congressional district against Republican Rodney Davis.

WATCH: American Action Network's New Ad: