Is this racist?

Yes, I think it is. 

The term "re-nig!" is a weak play off the word renege that means "to fail to carry out a promise or commitment." Its quite possible I'm being overly generous to the person who created the saying. What promise? Is the bumper sticker suggesting they don't want Obama to fulfill his promise? Its fuzzy at best and probably not the intended interpretation. More likely, they were using the prefix "re-" which means "again, anew" as in rebuild" or "backward" as in "renew." Given the graphic in the picture, its clear they don't want President Obama to be "re-elected." 

Which leaves us with the "nig" part. 

What else could it be except some slang of the word nigger? Seriously? I can't think of anything that makes sense and I doubt that anyone else can either. 

This certainly isn't indicative of all or even most Republicans, Conservatives, etc. Not at all, but this is the weakest form of protest. It takes virtually no intellect to produce garbage like this. It advances no discussion, no points of view, no lucid argument. None. Its just hatespeech. I'd find it damn uncomfortable to be an African American in a car behind that one. That's the kind of stuff that gets people dragged out of cars and roughed up. I know some will say "freedom of speech" to which I'd call bullshit. 

If a person dislikes Obama because of his policies or method of governance, that's fine. I can respect that. But for the people that find this cute or funny, what is there to say? Some people have not come to terms with the fact that an African American is the President of the United States.

When are we going to be rid of this nonsense?