What would have been an interesting political debate was ruined by the aggressive, bossy ____________.

The best choice in this context is "interviewer." The sentence suggests that a political debate was negatively impacted by someone who took on a dominating or assertive role during the proceedings. An interviewer is typically the person conducting the questioning in an interview situation, and if they are described as "aggressive" and "bossy," it implies they are overpowering the conversation and influencing the dynamics of the debate in an unfavorable way.

The other terms don’t fit quite as well in the context of a political debate. An "interviewee" refers to the person being questioned, which doesn't align with the idea of someone ruining a debate; rather, it would be the interviewer or the person conducting the debate who would have the more assertive role. An "interrogator" typically connotes a more intense, perhaps even hostile questioning style, often associated with police or legal situations, which doesn't quite capture the nature of a political debate. Lastly, "intervention" refers to the act of intervening or getting involved in a situation, but it doesn't refer to a person, making it unsuitable for this particular sentence structure.