Stewart's argument is that other artists such as Eric Clapton have written about cop killers (such as Eric Clapton) and still been invited to the White House.
But that argument bypasses the cop killer in question (Chesimard, who Common argues in the song is innocent and falsely accused) has a long record of violence, and fled to radical marxist Cuba, where she lives to this day. And that Common went to Cuba and visited the convicted escaped cop killer.
Common has written separate songs that lionize two separate cop killers(Chesimard, and Abu-Jamal), and another song that ("burn the Bush") similarly advocates killing then-president Bush.
But hey, y'know, other than that Common hasn't said anything that should exclude him from a White House invitation.
Common is also a member of Rev. Jeremiah Wright's church and indoctrinated in Black Liberation Theology, and thus yet another manifestation of Obama's ties to radicalism.
As if his lyrics advocating the killing of cops and Bush weren't enough.