When politicians resort to personal attacks, many editorialists criticize these attacks but most voters pay them scant attention.
Conclusion
Political commentators cannot be excused for mudslinging.
Evidence
Political commentators should be engaged in sustained and serious debate about ideas and policies.
In such a context, personal attacks on opponents serve not to beat those opponents but to cut off the debate.
Evaluate
Whenever we're reading a Main Conclusion (or Role) argument, we remind ourselves of their inverted tendency -- more than 80% of the time, the conclusion will be earlier than the evidence.
Specifically, we'll usually find the conclusion (on these two question types) in one of two places: - the very first sentence - attached to a Pivot / Rebuttal
We read the first sentence very intentionally, asking ourselves, "Does this sound like the author's opinion?"
Here, the first sentence sounds like a fact. The 2nd sentence has two claims, the first of which is presented as a given ("everyone knows X"). But the second claim in the 2nd sentence is an opinion:
Politicians can be excused for mudslinging.
Okay, that could be our conclusion. Does the author go on to support/defend that idea? No, he immediately pivots into a different opinion:
Political commentators cannot be excused for mudslinging.
Does this opinion get supported / defended? Yes, the final two sentences combine to provide reasons why political commentators shouldn't be engaged in personal attacks / mudslinging (those are essentially synonyms)
Goal
Find the answer that best matches the meaning of the 3rd sentence, "Political commentators cannot be excused for mudslinging".