Here's an article from the Washington Post that makes the case that all political contributions should be anonymous. The argument is simple, but with a twist: all contributions are filtered through the Federal Election Commission, and the source remains anonymous because the FEC will make it impossible for the recipient to know the identity of the source. What's more, if the identity of the contribution is ever found to have been disclosed, then fines and imprisonment can be imposed to enforce anonymity.
I think that if we really want to run with the idea that money is speech, this is the way to go. By not permitting a candidate for office to know who made the contributions, and filtering all contributions through a disinterested third party we can trust, the FEC, the candidate cannot exchange a political favor for a contribution.
There is another argument for anonymity which I hadn't considered before: intimidation. Michael Quinn Sullivan makes an interesting case for anonymous political contributions: when someone makes a large donation, it's a very public statement that can be met with intimidation and protests. But the entire premise of his argument is based on the assumption that money is speech. He would seem to be expression genuine concern about intimidation, but the problem with his argument is that he's surrounded by corruption investigations into him and the groups he supports.
The Supreme Court made it known in Citizens United that they were confident that voluntary disclosure would be the norm, but they were wrong. Dark money has become a huge concern, drowning out the merit of ideas and candidates in favor of creating a personal ATM for billionaires instead. Maybe the Washington Post is right. Maybe a blind donation system is the right way to go. Under the system they propose, people making donations will know who they're contributing to, but candidates will not know where the money comes from. That would also eliminate the problem of intimidation and allow us to prove once and for all whether there is any merit to unlimited contributions.
Even under idea conditions, I just don't see how it could work. Any campaign finance law with anti-disclosure provisions could easily be circumvented by secure communications protocols using very strong encryption. That is what is known as a dark network. All communications are encrypted, end to end, preventing anyone outside from ever knowing what information has been exchanged.
That's one reason why I disagree with the Supreme Court. There is another reason that doesn't get spelled out to clearly in debates on the subject. A billionaire making a contribution for a law he wants, that will favor his company or business over all others, is making a very selfish demand on the rest of the country. Such a demand is an expectation that the government will intervene in the market, on his behalf, at the expense of everyone else. If such a demand were made public, the donor could easily become a target of intimidation, public criticism and perhaps physical or violent threats. It is possible, for example, that a hacking group could attempt to conduct a campaign against the donor to damage his business or expose his secrets.
I have a friend who used to read latin dictionaries for fun. He'd learn latin, read the original text of stories from ancient Greece or Rome and consider them in the context of modern politics. His conclusion? "Same shit, different day." Even then, the Romans and the Greeks knew how tenuous democracy can be. They understood the power of influence and money in politics.
F.A. Hayek, in his book, "The Road to Serfdom", observed that a good law must be written in such a way so as to make it impossible to predict which individuals will benefit from it over all others. Dark money in politics thwarts that principle to no end. When the wealthiest of men and women can custom order the laws to be passed for their own benefit, every other citizen is disenfranchised of their right to representation. Under conditions imposed by dark money, we no longer have a democracy, we have an oligarchy.
One solution is complete and full disclosure of every true party in interest to every large contribution. There is another solution: limit campaign contributions from any single source to a reasonable amount, such as $250. You can have unlimited contributions with disclosure, or you can have anonymous contributions with a contribution limit. But if you allow unlimited anonymous contributions to political campaigns, then you get a ruling class that is unwilling to be accountable for their public policy mistakes.