Paul Light at Brookings has written on this subject. What I have read of his work leans toward the ill informed and Pollyannish, but then, so do most of the people who opine on the subject.
In my personal experience (Congressional staffer, Schedule C appointee, Career Fed), elected officials have a “trust but verify” relationship with bureaucrats. They start small with issues that will have little or no impact on their reelection. As they gain confidence the bureaucrats will not leak or deliberately undermine their proposals, elected officials will rely more heavily on them. In time, they may form close working relationships with career staff. But if they feel betrayed, even once, they will never trust that bureaucrat again and be much more cautious when dealing with others. Ironically, the career staff I trusted most as an appointee had previously held Congressional or appointed staff jobs with the opposite party. They shared my belief that elections are held to decide public policy, understood the pressure appointees work under and did everything possible to make my job easier not harder. Now that I am in a career position myself, I do my best to emulate their example. Unfortunately, I have also worked with entirely too many bureaucrats who took the opposite approach and set a very bad example. As an appointee, I knew of at least 3 who had the opposing party’s press office on speed dial. One stated in a strategic planning meeting that “public policy should not change just because there had been an election” (in which the party in power had been replaced). I have lost count of the number of times in each of my roles that bureaucrats made very clear their intention to slow walk policies directed by elected officials in anticipation of more favorable decisions from the next administration. As a career fed I make every possible effort to effectively implement the administration’s policies regardless of what I think of them. I understand that I have an obligation to EARN the trust of appointees. As a former appointee I understand they may be slow to extend that trust.