"We can harness similar benefits by creating a 'donation booth': a screen that forces donors to funnel campaign contributions through blind trusts," they wrote. "Like the voting booth, the donation booth would keep candidates from learning the identity of their supporters... A system of blind trusts would make it harder for candidates to sell access or influence because they would never know which donors had paid the price."
There is an obvious objection. It was reasonably simple to implement a secret ballot. But campaign contributions? What if it proved impossible to actually keep their provenance secret? What's to stop me from whispering to Joe Legislator, "You're going to see $10,000 show up in your campaign account a week from now. It's from me." That would be the worst of all worlds: gone would be the transparency of the current system, and politicians would still know who to keep happy!
After studying the issue, however, Larry Lessig concludes in his essential book Republic, Lost that anonymity is in fact possible to maintain. Citing "Voting with Dollars: A New Paradigm for Campaign Finance" by Bruce Ackerman and Ian Ayres, he writes that "the two critical elements are, first, an anonymous donation booth, which takes in contributions and then divides those contributions into random amounts, which it then passes along to the candidates;" that solves the "expect this amount on this day" problem; "and two, the right to revoke any contribution once made. It is this second element that does most of the work: for even if you watched me make the contribution to your campaign, I would still have an opportunity to revoke that contribution the next day. Once again, you're free to trust me when I say I haven't revoked it. But just as with vote buying, the need for trust will severely weaken the market."
Lessig concludes that anonymity would be maintained, and that this system ought to be tried -- I concur, and would love to see a state government experiment with it -- but curiously, he thinks that the reform would fail despite its technical efficacy. "My concern with this solution is not whether it would actually work. It would, in my view, for the architecture is genius. My concern instead is about whether it would be perceived to work," he writes. "For, if the core problem that dependence corruption creates is the perception among voters that 'money buys results in Congress,' then fighting that perception requires a system that the voters would understand, and believe. Yet we live in a nation where people don't even believe that voting machines are counting ballots accurately. To imagine the public understanding the brilliance of the anonymous donation booth, and believing that, in fact, there is no way for large contributors to prove they've made (and haven't revoked) a contribution, is, I believe, unrealistic. The mechanics are too complex; the sources of suspicion are too great."