A story from Frum

David Frum, National Review:

A president does not need to know everything. In fact, it's certainly impossible for him (or her) to know everything that he might possibly need to know. That's what the White House staff - and beyond them the whole vast apparatus of the US government - is for. Collectively, the US government knows a lot. And all of that knowledge is at the service and disposal of the president. All the president has to do is - is ask.

But that's not as easy as it sounds.

Somebody who knew President Bush well once remarked to me. "You'll notice he never asks questions."

"Why not?" I said.

"Because he doesn't know what it's okay for him not to know."