PT17.S2.Q11 - because an elected official needs

rogersalexandra7

So I chose answer choice A because author Q simply states, " ought to have been effective, but he has not been" the author is just saying that he's been ineffective but doesn't offer up any evidence as to why he is ineffective. Can someone explain to me why my reasoning is wrong? that would be greatly appreciated! thank you!!!!
https://7sage.com/lsat_explanations/lsat-17-section-2-question-11/

AllezAllez21

I would argue that Q does in fact offer evidence, it's just horrible evidence. Q uses their current legislator as a counterexample to P's reasoning. This counterexample serves as evidence, even though it's wholly ineffective.

Answer E describes the flaw that Q commits. Q confuses necessity and sufficiency. P says that legislators need a political party (necessity), whereas Q interprets that to mean that political parties ought to guarantee effectiveness (sufficiency).