Defense: Young has vendetta against Edwards

Both sides agreed at a pre-trial hearing that the video made by Edwards mistress Rielle Hunter should not be shown to jurors deciding whether the Democrat is guilty of campaign finance violations.

However, Edwards' defense team argued they should be free to question former campaign aide Andrew Young about inconsistent testimony he gave after Hunter sued him in state court to regain possession of the tape. The attorneys hope to use that testimony to undercut his credibility.

Young, who initially claimed paternity of the child Edwards fathered with Hunter, helped hide the pregnant mistress from the public during the 2008 presidential primary. He is now expected to be a key witness against his former boss.

The $900,000 secretly paid by two wealthy campaign donors to care for Hunter is at the heart of the six criminal counts against Edwards. He has pleaded not guilty, and jury selection for his trial is set to begin April 12.

Hunter sued Young and his wife in 2010 over control of the sex tape, which had been left at a property controlled by Young. He found the tape and later described it in a bestselling memoir.

During the resulting court fight, Young gave sometimes conflicting accounts of how many copies he made of the tape and how many people saw it.

A state judge found the Youngs in contempt of court for not following his orders to turn over all copies of the tape, though the contempt threat was dropped once the Youngs complied.

Prosecutors pointed out that the judge never said Young lied, and they argued that allowing statements to suggest such would only confuse the jury.

They asked that U.S. District Judge Catherine Eagles strictly limit what can be said about the sex tape case during Edwards' criminal trial. To do otherwise, they argued, could allow Edwards' lawyers to launch a "trial within a trial" strategy, using issues involving the sex tape to unfairly attack the government's witness.

Edwards' defense team said they believe Young has a bias and a vendetta against Edwards, and they want to prove that during trial.

Eagles did not indicate when she might rule on the issue.

Hunter and Young agreed to a civil settlement last month that requires all copies of the sex tape in possession of the North Carolina court to be destroyed. However, it has been suggested in court documents that Young previously gave a copy of the tape to federal investigators.

Prosecutors reaffirmed Monday that they have no intention of playing the tape in court, but suggested they may have to describe contents of the tape to jurors if defense attorneys question Young about testimony in the civil case.

That presents a dilemma for Edwards' defense team, if the potential damage to Young's credibility outweighs the possible harm to Edwards in describing the tape to jurors. Edwards' wife, Elizabeth, was dying of cancer when the tape was made.