WASHINGTON (CNN) - A lawyer for the tobacco industry Thursday attempted to paint the former commissioner of the Food and Drug Administration as a man who seized upon a political environment that was hostile to the tobacco industry in order to advance his own anti-tobacco agenda.

Dr. David Kessler, who led the agency from 1991 until 1997, appeared more interested in the publicity that his attempt to regulate Big Tobacco generated than he was about the science on which the decision was based, said David Bernick, a lawyer for Brown & Williamson Tobacco, one of six defendants in the $280 billion racketeering trial.

In the first day of what is expected to be a six-month trial, Kessler acknowledged under cross examination that he did not seek to regulate the industry until three years after he took the job, around the time media attention had raised the issue's profile and 17 years after anti-smoking groups had asked the agency to assume jurisdiction.

But Kessler told U.S. District Judge Gladys Kessler, who is no relation, that he sought the power for his agency only after he determined that cigarettes appeared to meet the definition of a drug.

Bernick pointed out that Kessler wrote in his 2001 book "A Question of Intent" that one of his colleagues had described his performance in congressional testimony as "kickass."

Kessler dismissed the comment as a simple attempt "to give the reader a sense of what people thought."

Bernick then implied that Kessler overreached in his role at the helm of the agency. The lawyer pointed to Kessler's reference in his book to his 1994 goals, which included: "Goad Congress into action."

"Is it within the statutory responsibility of FDA to goad Congress?" Bernick asked.

"The term 'goad Congress' is not in the statute," responded Kessler, who is currently dean of the medical school at the University of California at San Francisco.

Asked whether getting the FDA to regulate tobacco was his "personal goal," Kessler said, "It was the way I thought we should handle the issue."

In 2000, the Supreme Court decided the power to regulate tobacco did not fall within the agency's powers.

The repartee devolved into sarcasm when Bernick referred to Kessler's reference in his book to President Clinton's response after reading about the industry.

Kessler wrote that Clinton said, "I want to kill them."

"Did you tell the president at that time that that was not part of your job description?" asked Bernick, whose relentless drilling contrasted with Kessler's slow, methodical, halting answers.

"I did not respond to that directly," Kessler said.

Kessler had testified that a genetically engineered form of tobacco called Y-1 -- bred to contain higher nicotine levels -- appeared to be an attempt to hook smokers.

But Bernick pointed to records showing that Kessler -- in a telephone conversation with the scientist who worked on the project -- praised the work of the scientist who created the leaf in the 1980s and 1990s as pioneering.

In fact, Bernick said, the purpose of the leaf was not to hook smokers, but to create a safer cigarette. That effort was scuttled when test panels found smokers rejected the new leaf as unflavorful, he said.

Kessler had also testified that the tobacco companies added ammonia to tobacco in an attempt to increase the amount of nicotine released -- in essence, causing smokers to "freebase" on the drug.

Bernick took him to task for having little personal knowledge about nicotine chemistry, to which Kessler responded, "We based our knowledge on what the industry knew."

During much of the afternoon, the lawyer focused on a graph that Kessler had shown to Congress in 1994. It showed that the average nicotine content of cigarettes had risen from 1982 through 1990 even as tar levels were largely constant. Kessler had said that was evidence the industry was seeking to hook smokers by manipulating nicotine levels. "I was interested in whether there was a target dose of nicotine. It went to the question of whether it was a drug."

But Bernick showed data that extended back to 1950 that appeared to show the levels on Kessler's graph were an anomaly. "Did you have any idea that the picture would be completely different if you picked other dates?" Bernick asked.

"We graphed the data that the FTC [Federal Trade Commission] gave us," Kessler said.

On re-direct, Kessler pointed out to government lawyer Sharon Eubanks that the data in other years was provided by a Philip Morris executive.

The lawsuit was filed five years ago under Clinton. The defendants are the major cigarette companies in the United States including Altria Group, Inc.; Philip Morris USA, Inc.; R J Reynolds Tobacco Company ("RJR"); Brown & Williamson Tobacco Corporation (now merged with RJR); British American Tobacco (Investments), Ltd (as the former parent company of Brown & Williamson); Lorillard Tobacco Company; The Liggett Group, Inc.; The Council for Tobacco Research-U.S.A., Inc.; and The Tobacco Institute.

The Justice Department contends that the companies have conspired since 1953 to mislead the public about the perils of smoking. The $280 billion it is seeking represents "ill-gotten gains" -- profits from smokers who took up the habit before they were adults.

The companies reject the government's charges and say that, in the wake of the $246 billion Master Settlement Agreement with the states, they have become good corporate citizens.