Stern v. Marshall: Anna Nicole Smith claimed tortious interference against her late husband's son in probate court and then filed for bankruptcy. Pierce then counterclaimed in bankruptcy court for defamation. - Rule: Bankruptcy courts are not permitted to enter final judgment on state common law claims because it would be an impermissible delegation of Art. III power by Congress. o Distinguished from Schor because there can't be waiver in bankruptcy proceedings and bankruptcy doesn't require expertise.