I know, liberals.  It’s racist to say such provocative things about black people.  But setting aside the overabundance of PC, answer me this:

How is he wrong?

Seems like the metaphor is apt to me.  McNabb is a much-hyped NFL quarterback who has had nothing more than a mediocre career.  Barack Obama is a much-hyped politician who hasn’t accomplished anything more than getting elected to a Senate term he hasn’t even completed yet.