Kennedy called it an "attempt to stifle dissent."
Wesley Clark said the ad is wrong and ought to be pulled.
Sen. Joe Lieberman said the ad was misleading, nothing more than an attempt "to get the public's mind off the joblessness in America, the bad prescription Medicare drug bill ... the energy bill, which sells out to lobbyists."
RNC spokeswoman Christine Iverson said. "But we also have no doubt that they are wrong about that, and we will continue to highlight this critical policy difference as well as others."
