No one who lacks knowledge of a subject is competent to pass judgment on that subject. Since political know-how is a matter, not of adhering to technical rules, but of insight and style learned through apprenticeship and experience, only a particular political policy is fair to all.
What this question is testing
Conclusion
The author concludes only seasoned politicians can judge whether a policy is fair to everyone.
Evidence
The setup: you can't judge what you don't know. And political know-how is the kind of skill you only get through apprenticeship and experience — insight, style, the practical art of doing politics.
Evaluate
Watch the conclusion's wording carefully. The conclusion is about judging whether a policy is "fair to all" — i.e., its social impact, who benefits, who is harmed.
That's a different kind of question from "how do you do politics well." Doing politics well requires the practical know-how the argument describes — apprenticeship, insight, style. But judging whether a policy is fair to everyone requires understanding its social and ethical implications. A philosopher, an economist, or an affected citizen might have deep insight on social fairness without ever working as a politician.
The argument quietly treats these two kinds of expertise as if they were the same. That's the flaw.
Goal
Pick the answer that names the equation: political know-how is being treated as identical to understanding the social implications of policies.
Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.