Discuss as:

Edwards refused to lie about affair under oath, ex-aide testifies

Although several former aides testified that John Edwards lied to them about his affair Edwards' defense lawyer established that he wasn't willing to sign an affidavit denying paternity. NBC's Lisa Myers reports.

Updated at 7:10 p.m. ET: Prosecutors in John Edwards' campaign finance trial were thrown for a loop Thursday when a former aide testified that Edwards refused to lie under oath about his affair with Rielle Hunter.

Mark Kornblau, national press spokesman for on Edwards' 2008 presidential campaign, said he initially publicly denied reports of Edwards's affair in 2007 because he believed the story to be untrue. 

Things changed in December of that year, when a tabloid newspaper editor said he would stop publishing stories about the affair if Edwards would sign an affidavit swearing under oath that he wasn't the father of Hunter's daughter, Kornblau testified.

Edwards refused, Kornblau said. 

"Mr. Edwards would not sign an affidavit?" asked Edwards' chief defense lawyer, Abbe Lowell.

"He would not," Kornblau said.

The disclosure appeared to surprise prosecutor David Harbach, who asked Kornblau, "Is there a reason you didn't tell the government about the affidavit?"

"Because you never asked," Kornblau responded.

The surprise revelation came on the ninth day of Edwards' trial in U.S. District Court in Greensboro, N.C., where he is charged with six felony counts of accepting about $1 million in illegal and unreported campaign donations from two wealthy supporters.

The disclosure goes to the real issue of the case prosecutors are bringing, which seeks to persuade jurors that the donations — which were intended to support Hunter and keep her quiet about the affair — were in fact illegal contributions to the Edwards campaign.

"It's important because it shows that John Edwards was unwilling to break the law to help his candidacy for presidency of the United States," said Kieran Shanahan, a legal analyst for NBC station WNCN of Raleigh, N.C.

Edwards' legal team has acknowledged to the jurors that Edwards was a bad husband and a poor father. Its case rests on the contention that Edwards' behavior — while boorish — didn't violate any actual law, said Hampton Dellinger, a legal analyst for NBC News and msnbc.com.

"The government is not very far along in terms of surmounting that hurdle," said Dellinger, an expert in election law. "There has not been a single witness nor piece of documentary evidence that suggests that John Edwards knew or should have known that the money to his mistress constituted a federal election law crime."

And that was only the second major revelation Thursday.

Another former aide, John Davis, testified that Edwards scheduled a conference call in late 2007 to announce his withdrawal from the campaign, but his wife canceled the call even though she knew of the affair. Edwards ultimately dropped out of the race weeks later.

Davis said Edwards scheduled the call after a fight with his late wife, Elizabeth, in late 2007. But soon after, Elizabeth Edwards called a staff member to cancel the call, Davis said. Other witnesses have testified that John Edwards told Elizabeth Edwards about his infidelity in 2006. 

John Edwards, a former senator from North Carolina and the Democrats' nominee for vice president in 2004, remained in the race for several more weeks, eventually withdrawing on Jan. 30, 2008.

Davis told jurors that Fred Baron, finance chairman for the Edwards campaign, was also well aware of the affair with Hunter, testifying that he was present when Baron discussed Hunter by name before The National Enquirer published her identity in late 2007.

"The press wasn't going to find Ms. Hunter because of the way he was moving her around," Davis said, quoting Baron.

Former Democratic presidential candidate John Edwards has faced public and private challenges throughout his life and career.

As Edwards silently sat across from them on the campaign's plane, Davis said he asked Baron to stop talking, because "I didn't want to be aware of this."

Hunter was fired as a videographer on the campaign after Elizabeth Edwards spotted her at a campaign event, but she continued to visit Edwards on the road, Davis said, recounting that one night he ended up in the same elevator as Hunter was heading up to the candidate's hotel room. Later that night, Davis testified, she told him that she and Edwards were in love.

Davis said that when he asked Edwards about Hunter, Edwards told him that Hunter was "crazy" and that "we should make sure she didn't talk to him."

Davis also indicated that Edwards knew he was the father of Hunter's daughter as early as September 2007, saying he overheard Edwards ask her: "Can people tell? Are you showing?"

Edwards publicly denied paternity for Hunter's daughter for more than two years afterward, finally acknowledging that "I am the father" in January 2010, as the chief witness against him, former campaign aide Andrew Young, was preparing to publish a tell-all book.

By Lisa Myers and Stacey Klein of NBC News and M. Alex Johnson of msnbc.com. Follow M. Alex Johnson on Twitter and Facebook.

More content from msnbc.com and NBC News:

Follow US News on msnbc.com on Twitter and Facebook