The Citizens United case affirmed that a private group could collectively spend money to produce and distribute a movie attacking Hillary Clinton during her campaign.
The problem is, if you want to stop those people from spending money to influence the outcome of elections, you must also forbid the New York Times from doing so. That means no investigative journalism, no exposés of candidates, no endorsements or political op-eds. Ink and paper cost money, and that money is spent by a corporation.
(And, if you succeed in letting newspapers have a regulatory carve-out, then all you’ve done is make them tasty acquisition targets for those same corporate interests you just tried to restrict.)
I think unlimited spending on political messaging has poisoned our politics and our culture, but I think that’s downstream of a lot of other factors — the loss of social cohesion, weakening of civil society and institutions, and the growth of federal power raising the stakes of elections. Restricting speech won’t solve these issues. I’m not sure what will.