The federal government's ticket-fixing case against former state senator Willard J. Moody and state Sen. John S. Joannou, as outlined in defense arguments here today, is built solely upon circumstantial evidence and the testimony of a man described by prosecutors themselves as a scoundrel.

Joseph Aronica, an assistant U.S. attorney, told jurors that if they used common sense and did not give in to sympathy for politicians in trouble, they would convict Moody and Joannou for allegedly using phony speedometer calibration certificates to get the speeding charges of friends and relatives dismissed.

The defense told jurors the only way they could come up with a guilty verdict was by wholesale guesswork and acceptance of what Joannou's attorney, Frederick (Bingo) Stant Jr., called "enough lies to fill a Bible."

The jury deliberated for two hours last night before adjourning for the day. The two Portsmouth lawyers are accused of conspiring with Clarence Mixon, who owned a car dealership with Moody, to distribute the phony certificates that purported to show inaccurate speedometers.

Moody, 60, who retired last year from an influential position in the General Assembly, faces a total of eight counts of conspiracy, mail fraud, perjury and obstruction of justice. Joannou, 44, apparently the only Virginia state senator to be indicted on felony charges while in office, faces one charge of conspiracy and 12 counts of mail fraud.

Of more than 60 witnesses who have testified during their trial, now in its ninth day, only Mixon has said that Moody and Joannou knew the certificates were phony and U.S. District Court Judge Richard L. Williams has cautioned jurors that his testimony is "open to suspicion."

Mixon has admitted lying repeatedly under oath in the past, telling a grand jury a different story about the role of Moody and Joannou in the scam and participating in a wide range of other schemes.

Without Mixon, the four lead defense attorneys argued, the whole case collapses. And Mixon is someone who, according to other witnesses, would stoop so low as to steal potato chips off a truck and ". . . There isn't a strong enough perfume to get the smell off that liar." -- Defense attorney James Roberts siphon gas out of his customers' cars at the dealership.

"The government has brought him in here. They put a tie on him, they gave him a bath, but they couldn't clean him up enough to be believable," said James C. Roberts, one of Moody's attorneys. "There ain't a strong enough soap, there isn't a strong enough perfume to get the smell off that liar."

But Aronica argued today that Mixon's testimony is the only explanation for the circumstances laid out in the trial.

If Moody and Joannou thought the dealership's certificates were valid as they claim, Aronica asked the jurors, why would they tell Mixon how much over the speed limit a client was traveling when they sought calibration? Mixon would have no need for that information if the dealership was actually checking the speedometers, Aronica argued.

And if Robert J. Haley, an associate in Joannou's law firm, and John Ashworth, who worked in Moody's firm, could tell the certificates were phony, Aronica asked, why couldn't Moody and Joannou?

"These defendants are intelligent men; they're not naive," said Assistant U.S. Attorney Robert Seidel. "They want you to believe they blindly did what Clarence Mixon told them," Aronica said. " . . . Total nonsense."

Defense attorneys referred to such arguments as "slender reeds" of innuendo that together with Mixon's "preposterous lies" form the embarrassingly feeble support for the government's case.

Roberts vigorously attacked inconsistencies in Mixon's testimony. He contrasted Mixon's testimony during the trial that Joannou approached him first about the scheme with his testimony to a grand jury in 1983 that Moody came to him first.

Roberts also cited testimony from two witnesses that Mixon distributed phony calibration certificates in the early '70s, several years before he alleges he, Moody and Joannou thought up the scheme.

Though their attorney described both Moody and Joannou as exemplary citizens and the "personification of the American dream," Aronica told the jurors "they both associated with him. And what does that tell you about them?" he asked.