The only problem with limiting responsibility to career bureaucrats is that the heads of agencies ARE responsible for what goes on in their agency. If they are not aware of it then it is dereliction of duty. They are SUPPOSED to know about major projects. The troubling thing is how could an operation that involves foreign parties and govts NOT be on the radar of heads of ATF, DEA, and State?
If mid-level managers were able to pull this off without director approval then those agencies are in serious need of overhaul. Somehow I don't find that scenario credible.
At any rate, regardless of whether they knew what was going on in their own agency, directors are responsible for such large programs that involve another country and drug cartels and should be held to account.
"The ultimate authority ... resides in the people alone. ... The advantage of being armed, which the Americans possess over the people of almost every other nation ... forms a barrier against the enterprises of ambition."
- James Madison