Roy Lee Williams' chief defense lawyer charged today that the ailing Teamsters union president was being prosecuted for a bribe offer that was never made and urged his jurors to vindicate him before he dies.

"He doesn't have a lot of time left," attorney Thomas Wadden told the jury in an emotional and compelling summation at Williams' bribery-conspiracy trial here. "He's 67. I think you can see some of his problems in the courtroom. I hope, ladies and gentlemen, that in reaching your verdict, you won't turn lights out on Roy Williams. He's got a few dreams left."

The government has charged that Williams and four other defendants conspired to bribe Sen. Howard W. Cannon (D-Nev.) in 1979 in return for Cannon's help in blocking trucking deregulation legislation. Wadden denounced it as "a lousy case" that was brought in a futile effort to block Williams' election last year.

Williams, who suffers from emphysema, was appointed interim president of the Teamsters on May 15, 1981, following the death of Frank Fitzsimmons. The bribery indictment was returned a week later, on May 22. Despite the charges, Williams was elected to a full term on June 1, 1981, at a Teamsters convention in Las Vegas.

"Mr. Williams certainly made one mistake in this case -- one big mistake -- when he decided to run for the presidency of the largest union in the Free World," Wadden declared. He stressed that Williams and Cannon had never met each other before a Jan. 10, 1979, get-together in Cannon's office. Wadden scoffed at the government's claim that they "cut a deal" with each other on such short acquaintance.

Indicted with Williams were Chicago insurance executive Allen M. Dorfman, a longtime Teamsters union associate who arranged and attended the meeting with Cannon; reputed Chicago mobster Joseph Lombardo, a frequent visitor at Dorfman's insurance offices in the Teamsters Central States Pension Fund building here, and two other men, Amos Massa, a former trustee of the $3.5 billion fund, and Thomas G. O'Malley, a current trustee.

The government built its case largely on the results of a court-ordered wiretapping and bugging of Dorfman's telephones and offices. The year-long surveillance, which began Jan. 30, 1979, produced a number of tape-recorded conversations in which Williams could be heard speaking of the "commitment" to Cannon and Dorfman complaining again and again of the Teamsters' failure to deliver.

Wadden maintained that all Cannon had been promised was a "fair chance" to bid on a piece of Teamsters pension fund property in Las Vegas that the senator and his neighbors wanted to buy since it was located near their homes and had been proposed for high-rise development.

The government charged that the senator had actually been promised exclusive rights to purchase the property for a below-market price of $1.4 million.

Wadden acknowledged that an aide to Dorfman, William Webbe, who was in Cannon's suite at the time, recalled in one FBI-recorded conversation that Williams had told Cannon, "You take care of your end and we'll take care of ours. You don't have to worry about a thing."

Wadden said he wouldn't believe anything Webbe said. "I think he has the genes of a used car dealer, the mind of a fox, and the smell of a skunk," Wadden protested.

Dorfman's lawyer, Harvey Silets, also dismissed the government's tapes as a misleading compilation of "heated words, boasts, exaggerations, puffing and bull manure." He said Dorfman had a habit of bandying about big names and claiming influential connections, as the FBI tapes showed him doing repeatedly in regard to Cannon.

In rebuttal, prosecutor Gary Shapiro told the jurors that the defendants "are trying to get you to ignore the evidence in this case." He maintained that the spontaneous conversations on the tapes were much more believable than the denials and faint recollections voiced from the witness stand over the past eight weeks.

The case is expected to go to the jury Saturday.