They claim Carona's actions fell short of violating the statute.
The judge is expected to make his ruling by Tuesday.
On January 16, Carona was convicted of witness tampering, but acquitted of other charges including conspiracy, mail fraud and obstruction of justice.
Prosecutors had accused him of conspiring with his wife and mistress to appoint millionaire Don Haidl to the post of Assistant Sheriff in exchange for cash and gifts.
The case against the women was later dismissed.
Carona's single conviction stems from a secretly recorded conversation between Haidl and Carona.
Carona's attorney, Jeffrey Rawitz, says, during that meeting, his client never expressly asked Haidl to lie to the grand jury.
He wrote, "Persuading a witness to give false testimony is not the same thing as persuading a witness to withhold testimony."
The defense papers also argue that prosecutors used unethical means to get Carona to talk and that Haidl lacks credibility as a witness because he was cooperating with prosecutors to reduce his own sentence on a tax charge.
Carona is currently free on a $20,000 bond.
His sentencing is scheduled for April 27.
Defense attorneys say Carona should receive probation if the charge is not dismissed.
Federal probation officers recommend that he serve 6 1/2 years in prison.
City News Service contributed to this story.
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