"Words matter, and the insurance industry is a master at linguistics and using the hot words, buzzwords, buzz expressions that they know will get people upset," he told CNN Wednesday.

Now a senior fellow on health care for the watchdog group Center for Media and Democracy, Potter writes a blog on health care reform. He is focusing on efforts to defeat legislation supporting a government health care plan -- something he supports.

In early July, Potter testified before the Senate Commerce Committee, telling senators that "I know from personal experience that members of Congress and the public have good reason to question the honesty and trustworthiness of the insurance industry."

Potter described how underwriters at his former company would drive small businesses with expensive insurance claims to dump their policies. Industry executives refer to the practice as "purging," Potter said.

"When that business comes up for renewal, the underwriters jack the rates up so much, the employer has no choice but to drop insurance," Potter had said.

In an e-mail to CNN, Cigna spokesman Chris Curran denied the company engages in purging.

"We do not practice that. We will offer rates that are reflective of the competitive group health insurance market. We always encourage our clients to compare our proposed rates to those available from other carriers," Curran wrote.

But now, Potter is back in Washington at the invitation from Rep. Louise Slaughter, D-New York. He is questioning insurance companies' public relations tactics -- and says some of the questions from town hall meetings are familiar.

"People talk about the government takeover of the system ... that's a buzz term that comes straight out of the insurance industry," he said.

A Cigna spokesman would not comment directly on Potter's accusations. Instead, the company released a written statement saying officials agree that health care reform is needed. But the statement went on to say that officials don't see how a government-sponsored plan can accomplish that.

But Potter's concerns fall right in line with the Democrats' strategy of hitting insurance companies hard this summer. Republicans argue that insurance companies aren't solely to blame for the health care crisis, noting that many of their constituents are perfectly happy with the current system.

The Democratic Party is also dealing with a group of fiscally conservative members known as "Blue Dogs" who are worried over the high costs of the health care plans being bandied about.

Slaughter says that the concerns over a government option may be set up to "try and protect one industry" -- referring to the health insurance industry.

Potter insists he has no agenda -- just a deep passion for the issue.

"This is hard to do. It's scary to do something like this. I don't think I'm any more courageous than anybody but I feel I had to do this."

Potter also has said he decided to resign in 2007 after Cigna's controversial handling of an insurance claim made by the family of a California teenager, Nataline Sarkysian.

The Sarkysian family made repeated appeals at news conferences for Cigna to approve a liver transplant for the 17-year-old, who had leukemia. Cigna initially declined to cover the operation, then reversed its decision.