It's easy to say that corporations are not people (they aren't), but harder--if you stop to think about it--to say that corporations don't have First Amendment rights, or something like them. Would we really say that General Motors should not be permitted to argue against CAFE (corporate average fuel economy) standards? Or even to comment on global warming? Surely, corporations must have some right to express views on matters involving their business interests. And what standard can we use to winnow out protected from unprotected corporate speech?
I suggest that corporations should be permitted to comment on issues, and to support efforts directed to issues--such as referenda, even though I am uncomfortable with the idea of corporate interests participating in elections of any kind. Still, the distinction between corporations and people--real people--is most clear when we distinguish issues from candidates. Issues are specific; candidates who become office holders have sway over all matters that may arise.
In this respect, one of the one-man-one-vote cases, Reynolds v. Sims, 377 U.S. 533, 580 (1964), is especially apt. There, Chief Justice Earl Warren observed that "Citizens, not history or economic interests cast votes...people not land or trees or pastures, vote."