Monica Youn has posted this draft on SSRN (forthcoming, Harvard Law & Policy Review). Here is the abstract:

This Article argues that in answering the recurring central question of campaign finance doctrine–the question of whether political spending can be treated as speech and, if so, when and to what degree–the Court has employed two competing accounts of First Amendment value. Under the first of these theories, which I call the volitional account, the source of First Amendment value is the volitional impulse of the spender: the spender voluntarily dedicates an expenditure to a particular expressive purpose, thus generating First Amendment value in that particular expenditure. Under the second theory, which I call the commodity account, the market is the source of First Amendment value, which is quantified externally through market measures, such as dollar value, rather than through such individualistic and subjective measures as volition or intensity.
Citizens United marks a new high point for the commodity account and, moreover, presents a major extension of that theory by setting forth a “source-blind” approach to the regulation of money in politics that forbids the state from differentiating among different sources of political spending. The source-blind approach adopted in Citizens United appears to be profoundly at odds with the volitional account of First Amendment value underlying much campaign finance doctrine–the volitional approach requires an inquiry into the degree to which a funding source can be deemed to advance the volitional impulse of the spender; the source-blind approach would seem to forbid such inquiry. This Article concludes by suggesting some of the destabilizing ramifications of this source-blind approach as a First Amendment theory that excludes any volitional considerations.