Patrick Kennedy, the former congressman from Rhode Island, said the shooting in Tucson, Ariz. has pushed the threat level to members of Congress to an "all-time high" and members are in fear about running for office.
"It steals from democracy," he said, "when you have my colleagues decide not to run for re-election because they're worried about their personal safety.
"This is a major issue because it's got nothing to do just with the personal tragedy of Gabby, but the tragedy to our democracy when people are fearful of the political process."
In an exclusive interview with ABC News' Christiane Amanpour, Kennedy said some members of Congress have been receiving public threats for years, and that "politician" is "an evil word now."
"Some of my colleagues, people don't know about it, were getting 'round the clock protection for some time," he said. "What it represented to me was a change in just the environment."
He added that he and other members have been aware that the atmosphere of today's politics could eventually ignite a "violent act," such as what happened in Tucson.
"We've lived in an environment that sanctioned pretty heated rhetoric," he explained. "That's really bordering on irresponsible in how much it condones violence and the dehumanization of our political leaders."