Presumably, like in a court of law, there could be rules and restrictions about what sort of arguments you're allowed to make in front of the jury. Just like there's some evidence and arguments that are inadmissible in court, various things (Bribery, threats, ad-hominem attacks) could be inadmissible in Congress. I haven't thought through all the implications, and you'd probably need a "judge" to interpret and enforce those restrictions.