The desire for consensus is generally strong but sometimes DOS 'guidance' leaves little room for maneuver. As John T illustrates, there are sometimes personal connections that transcend the normal chain.

Stan is correct on the leadership issue -- but a weak Ambassador can be 'led' by an astute Political Counselor (one case) or CIA Station Chief (another case). An overly belligerent DAO can wreak havoc (a third case) with even a good and strong Ambassador. Surprisingly, in all three cases, IMO the net result was positive for the US.