Judge Richard Posner has written this review of Justice Breyer’s book, Active Liberty. A snippet of interest to election law:

Breyer does not discuss the particulars of campaign finance reform. He is content to argue that placing some limits on contributions to political campaigns should not be held to infringe freedom of speech. He recognizes that to tell someone you can’t spend $1 million to buy a commercial extolling the candidate of your choice curtails expression; but he thinks that limiting the ability of the rich to spend unlimited amounts on campaign advertising is justified by its contribution to active liberty. Interpreted in the light of active liberty, the First Amendment is to be understood “as seeking to facilitate a conversation among ordinary citizens that will encourage their informed participation in the electoral process,”20 and campaign finance laws have a “similar objective””21 They “seek to democratize the influence that money can bring to bear upon the electoral process, thereby building public confidence in that process, broadening the base of a candidate’s meaningful financial support, and encouraging greater public participation.”22 This is a little vague, but the basic idea seems to be that if there are no limitations on individual campaign contributions, candidates will confine their fundraising to a handful of fat cats and the ordinary people will become disaffected–alienated from the political process–because they will assume that policy is shaped by the interests of the rich and that the people’s voice is not heard.
No evidence for this speculation is offered, and it is not very plausible. For one thing, the wealthy are not a monolith; they have competing interests. For another, they do not have the votes, and so their political advertisements are aimed at average people–and it is odd to think that the fewer political advertisements there are, the greater the amount of political participation there will be. That is like thinking that curtailing commercial advertising would result in more consumption. Furthermore, if some candidates court the wealthy, others will be spurred to raise money from the nonwealthy–something the Internet has made easier to do, as we learned in the last presidential election.
I am not suggesting that Breyer is wrong to think that campaign finance laws do not violate the First Amendment. If there is no evidence that they promote active liberty, there is also no evidence that they curtail free speech
significantly. I am old fashioned in regarding the invalidation of a federal statute as a momentous step that should not be taken unless the unconstitutionality of the statute is clear, and the unconstitutionality of campaign finance laws is not clear. But active liberty does not advance the analysis because it does not yield an administrable standard. Breyer tells us that the proper standard for judging the constitutionality of a campaign finance law is one of “proportionality.”23 The law’s “negative impact upon those primarily wealthier citizens who wish to engage in more electoral communication” is
weighed against its positive impact upon the public’s confidence in, and ability to communicate through, the electoral process. . . . Does the statute strike a reasonable balance between electoral speech-restricting and speech enhancing consequences? Or does it instead impose restrictions on speech that are disproportionate when measured against their electoral and speech-related benefits, taking into account the kind, the importance, and the extent of those benefits, as well as the need for the restriction in order to secure them?24

“The inquiry is complex,” writes Breyer.25 No; it is indeterminate.