Ambassadors not only serve at the pleasure of the president. They are the president's voice. They are suppose to echo his policies which are the people's policies. The president is elected. Ambassadors are not. If they can't support the president's views, they should resign. If they screw up, the president takes the hit, not them, like when Saddam Hussein invaded Kuwait thinking he got an OK from the American ambassador that America would look the other way. In that case, an ambassador's screw-up caused a war that the president had to to correct.
How many here would go against their boss's requests and ignore their policies?