I realize that initials like JFK or LBJ or GWB don't exactly roll easily off the tongue as dog names. Still if any of these presidents had named their dogs after themselves, wouldn't it have been perceived as a sign of an ego one size too large even for a president?
And yet Barack Obama's dog's name is Bo, i.e. the president's initials, but then nothing could be more fitting for a man who loves himself so deeply, and whose narcissism may well be clinically diagnosable.
One amusing note: LBJ was given a dog by J. Edgar Hoover, which the president then named J. Edgar. At least LBJ knew (just slightly) that it wasn't all about him.