Obama could have killed the ambassador himself, and not be impeached.
They would never impeach a black President. If it even started to look like a possibility, the MSM and the Democrats would pull out all the stops, including heavy use of the race card. Remove a black President because he didn’t stop four “crackers” from being killed? Then start talking about how many died as a result of Bush’s invasion of Iraq.
Effectively, he did kill him himself, he and Hillary.
But that Obama would ever have the decency to resign is about as likely as Ben Crump admitting that he made up DeeDee's conversation with Trayvon.