A “Policy Wonk” is a government official/consultant who is “very knowledgeable” on a single subject. I refuse to use the term “expert” because that title is usually-self-declared.
Before I get into this, I need to clarify the difference between "Authority" and "Responsibility," which the Navy pounded into me every day. Authority can be delegated, responsibility cannot. The Captain of a ship can delegate the authority to helm the ship as the Officer of the Deck to an Ensign. It is the job of the captain to make sure the Ensign has the knowledge, skills, wisdom and judgement to safely steer the ship and stay within the rules of navigation and the Captain's general orders. If the Ensign runs the ship aground (or into another ship, etc.), the Captain pays the price for the act. The Ensign will get yelled at by the Captain, but will not get yelled at by the Admirals. Back to the subject at hand.
I am reminded of an episode of The West Wing, where President Bartlett was facing the looming probability of a recession. He spends the episode talking with a multitude of his policy wonks on how to avoid this recession. Their answers were unanimous, “The last guy you talked to is an idiot. His ‘solution’ will cause long-term problems here, here and here, making things worse. What I suggest is you hammer hard on the one aspect of the economy I am an expert on and that will fix the problem." President Bartlett, as all good leaders do, said, “Maybe the answer is not to hit one part hard, but to hit all of them gently and at the same time.”
Trump screwed up big time when he let a single medical policy wonk dictate economic policy. I can see the furrowed brows from here. Making people stay home and not go to work when a new infectious disease we "know nothing about" *cough*BULLSHIT*cough* might be a reasonable medical policy, but it carries grave economic consequences that Fauci does not have the training or knowledge to consider fully. That being said, there's the "superpower" called "common sense" that should have entered into Fauci's calculations. Obviously Fauci lacks that superpower. And because any economists Trump may have consulted deferred to Fauci, rather than provide Trump the context and ramifications on a possible course of action. Or, it is possible Trump ignored the economists or never even consulted them.
MAKING POLICY AND DECISIONS IS WHAT POLITICIANS ARE SUPPOSED TO DO. THAT'S THEIR JOB. Politicians are elected to office because a majority of the people believe this person to be the best candidate out of those provided to make good and proper decisions in a timely manner. While the politician should consult with a multitude of advisors before making any decision, the decision must ultimately be made by the politician.
The job of the wonk is to advise, then follow the directives of the politician, for good or bad. To tell a single wonk “Take care of this as you see fit” is the worst decision the politician can make. Because the wonk, pounding on one thing, will make so many other things go bad, and the politician gets all the blame when things go sideways.