Comment by niam

"Money is speech" is kind of a misleading interpretation because it comes with all sorts of baggage that people typically infer from a thing "being speech".

Phrased another way: the argument is that limiting one's ability to spend is practically a limitation on their speech (or their ability to reach an audience, which is an important part of speech). If some president can preclude you from buying billboards, or web servers, or soapboxes on which to stand: he has a pretty strong chokehold on your ability to disseminate a political message.

I'm not defending that argument, only saying what it is as I understand it.