Should Corporations Have First Amendment Rights?

As Professor Winkler correctly stated, current doctrine emphasizes the rights of listeners rather than the identity of corporate speakers. My argument is, in effect, that this emphasis misses the key point. But I will not deal with listeners directly. I am simply going to assume, rather than argue, that if corporate advertising were ineffective in influencing voters or legislators, normal market processes would eliminate it.

I'm going to take it for granted that when corporations speak, it makes a difference in the actual results.