John McCain in a letter the North Carolina GOP says the following:

“I have been committed to running a respectful campaign based upon an honest debate about the great issues confronting America today. I expect all state parties to do so as well. The television advertisement you are planning to air degrades our civics and distracts us from the very real differences we have with the Democrats”.

UPDATE: The NCGOP says they will run it anyway.

UPDATE II: Mark Mays doesn't think the ad is so fierce:

As far as attack ads go, it is fairly tame. Clinton’s ad, “waving the bloody shirt of 9/11,” was rougher. A Democrat attack ad being tougher on another Democrat than a Republican attack ad? That’s how we roll.