Mark, maybe we should distinguish between trusting the bureaucracy, and trusting the person of contact for the bureacracy the elected official deals with. The first doesn't matter that much, at least in my experience in Canada. Elected officials federally and provincially don't interact with the bureacracy except primarily through the Deputy Minister, so the relationship of the DM to the minister is the one important one.
As for some of the other comments, I see a whole lot of stereotyping here. In Canada, the elected official (minister), and Deputy have a relationship where the Minister, in effect has to rely on the DM, and ADM's. And it's an interesting relationship because the DM in a department doesn't report to the Minister, and almost always outlasts him or her. Politicians come and go, but DM's tend to stay.
The idea of an independent civil service is critical to our canadian democracy, and I've seen little of the politicization of the civil service in Canada, that people seem to talk about happening in the USA.
At least in Canada, senior civil servants will derive no benefit for embarrassing or blocking the ideas of elected officials, just because. It's the opposite. I know of many stories where senior civil service execs have gone out of their ways to save humiliation for the political arm of government. I'll share some of them, but frankly I'd discouraged at the lack of dialogue on govloop.