What is the current state of the law on prosecutorial misconduct in the context of inflammatory or insinuating questions and statements?

This court has repeatedly addressed itself to the problem of prosecutorial misbehavior in the form of inflammatory or insinuating questions and statements. United States v. Bivona, 487 F.2d 443 (2d Cir. 1973); United States v. White, 486 F.2d 204 (2d Cir. 1973); United States v. Drummond, 481 F.2d 62 (2d Cir. 1973). We have consistently warned that such misconduct may constitute sufficient cause for reversal.