Opening arguments were heard Monday in the case to decide whether former senator and presidential candidate John Edwards misused campaign funds to cover up an extramarital affair.

Edwards, 58, pleaded not guilty to the six felony charges. He's accused of using nearly $1 million in secret payments to hide his pregnant mistress during the 2008 election season.

The North Carolina Democrat admitted to his moral failings but insists he didn't break the law.

Prosecutors are expected to argue that Edwards masterminded the cover-up. Meanwhile, Edwards denies he knew about the money or where it came from.

The trial is expected to last about six weeks. Obama-appointed U.S. District Court Judge Catherine C. Eagles will preside over the case.

Defense lawyers haven't decided whether Edwards will take the stand.