Zephyr Teachout, in Gifts, Offices, and Corruption, 107 Nw. U. L. Rev. Colloquy 30 (2012), replies to Seth Barrett Tillman in their discussion of Citizens United v. Federal Election Commission, 558 U.S. 50 (2010). Teachout's paper is available for download at the Northwestern University Law Review and at the Social Science Research Network.
Here is our post on Tillman's opening statement.