P: Because an elected official needs the support of a political party to be effective, the independent candidate for the legislature cannot possibly be an effective legislator is she wins.
P's Conclusion
An indie candidate can't possibly be an effective legislator in office.
P's Evidence (because)
To be effective, elected officials need the support of a political party.
Q's statement
According to your logic, if someone (like our current legislator) has the support of a political party, they will be effective.
Evaluate
When they ask us to criticize the 2nd person's response, the 2nd person is usually guilty of some bad listening.
They might misrepresent what the first person said, fail to respond to their substantive concern, or say something irrelevant.
In this case, Q is misrepresenting what P said.
P said
Q accuses P of saying .
This is the classic Necessary vs. Sufficient confusion. P identified "support from a political party" as something necessary to be effective. P never suggested that such support was sufficient to guarantee that someone would be effective.
P is saying "Without support, they won't be effective" not "With support, they're bound to be effective" as Q is saying.
Consider the difference between saying and saying
Goal
Look for an answer calling out the Necessary vs. Sufficient distortion. P only said that support was required, not that it would guarantee effectiveness.