Thomas Stratmann has sent me “Ballot Access Restrictions and Candidate Entry in Elections,” 21 European Journal of Political Economy 59 (2005). From the abstract:

In many states of the United States, candidates must meet certain requirements in order to be listed on the ballot. Such requirements include filing fees and minimum number of collected signatures. Incumbents have incentives to use these requirements to protect themselves from competition by reducing entry of potential challengers. To date, there is very little evidence regarding whether such requirements have negative consequences for candidate competition in elections and challenger entry into electoral races. This paper examines the impact of filing fees and signature requirements on the number of candidates in U.S. state races in state Lower House elections in 1998 and 2000. The findings show that higher filing fees reduce both the number of major-party and minor-party candidates. However, filing fees are more effective in deterring minor-party candidates from contesting political office than major-party candidates. More stringent signature requirements reduce the number of major-party candidates

Michael Kang has sent me three articles (besides a book review in ELJ that I’ve already noted):
The Bright Side of Partisan Gerrymandering, 14 Cornell Journal of Law and Public Policy 443 (2005)
From Broadcasting to Narrowcasting: The Emerging Challenge for Campaign Finance Law, 73 George Washington Law Review 1070 (2005)
The Hydraulics and Politics of Party Regulation, 91 Iowa Law Review 131 (2005).