This is brilliant! In this way, the right to put your money where your political beliefs are is not infringed, and there's absolutely no way to tell which group gave how much and to whom!
All incentives for quid pro quo deals vanish under this splendidly common-sense solution (although there would have to be strict non-disclosure regulations,* to prevent back-stairs information on "who is Uncle Gotbucks this week?" from getting to candidates), while avoiding the very real constitutional problem of inhibiting political speech.
Well done, Mr. Secretary! Now, if you'd just get it through your extremely clever head that your much despised "tax breaks for the rich" translate, in real-world economics, into "lower interest rates on everything consumers finance from homes and cars to college loans and car insurance," we'd be agreeing nearly all the time!
* A word from the Department of Redundant Irony Department: This plan's obverse twin, the unfortunately Delay-Doolittle Bill, would have had equally strict disclosure requirements, by making the source of every single donation a matter of public record. These days, with the Internet running full throttle, this plan would work like a charm: I don't care how much money the candidate spends, I just want to know if Ayran Nation or Louis Farrahkan donated any of it ... Of course, Delay-Doolittle died in the mid 1990s, in committee if memory serves. Oh well, I'll take its evil twin, the Reich Solution, and be glad of the similar result.