The federal government (plaintiff) prosecuted Leslie Mayfield (defendant) for conspiracy and firearm offenses, in violation of 18 U.S.C. §§ 846, 922(g)(1), and 924(c)(1)(A). The federal district court trial evidence established that Mayfield's criminal record included convictions for robbing illegal-drug stash-houses. Witness Jeffrey Potts testified that, acting undercover for the government, he offered Mayfield a chance to help him and his co-conspirator rob another stash-house. According to Potts, Mayfield agreed, helped plan and prepare for the robbery, and assembled the conspirators' arsenal. Mayfield proffered testimony that despite his criminal record, he had since gone straight, spurned Potts' persistent invitations to join the conspiracy, and agreed to do so only after Potts implicitly threatened Mayfield if he did not. According to Mayfield, Potts coached him on what to say at the planning meetings and gave Mayfield the weapons for his arsenal. The judge granted the government's motion in limine to exclude Mayfield's proffered evidence. The jury found Mayfield guilty, and he appealed to the Seventh Circuit Court of Appeals. By a split vote, a panel of judges upheld the conviction. The full court granted Mayfield's motion for rehearing en banc.