I’m no attorney, but my understanding is that political campaign donations are largely considered to be speech. If I understand correctly, the idea is that the First Amendment not only gives me the right to speak, it also gives me the right to let someone else speak for me. Since I can use my resources to publicize my own speech, I should be able to use my resources to publicize speech someone else makes in my stead.
There’s a problem with that… There are costs to speech. For example, I can say I think Greg Mankiw is a hack and there will likely be no consequences. However, if I outright call Greg Mankiw a hack, I can be sued for libel.
Similarly, if a PAC calls a Jack a hack, the Jack can whack the PAC with a suit. But, I, as a donor, am not subject to the suit. So if donating money to a PAC is free speech, it seems to be a very strange kind of free speech, one with no consequences. I would think it makes sense to either put limits on money in politics, or to open up donations to the same sort of libel laws to which regular speech is subject.