But if corporations aren't people, then physically they can't speak, so you will have no worries. They will never, with or without Citizens United, affect an election.
But maybe they can speak like a robot! But would programming a robot to speak be protected speech? I assume so. Why? - because a person had to program it. Indeed, we really already have mechanical speech, as when recordings play a message over and over, or as when a person posts a political video on YouTube that others can then watch. I presume that a deaf/mute person would be protected in programming a robot to make audible political statements on his behalf that, he feels, would be an effective way for him to communicate.
Of course, the reality is that corporations are made up of people, and people have a right to associate, and associations of people have a right to speak. And corporate personhood does not stem from a decision that never examined the issue. I know that's Tom Hartmann's view, but Hartmann is neither a lawyer nor an historian, and it's just not true. The idea of corporate personhood has existed since the nation's founding, and is well grounded in legal theory, history, and precedent.