Another indicator of how Section 5 plays into closed-door decision making can be found in a 2007 study by Nathaniel Persily, a professor of law and political science at Columbia University. Persily bore into the 800 cases since 1982 in which the Justice Department requested additional information about proposals for electoral-system changes under Section 5. In more than a quarter of them, he found the proposals were withdrawn. While this is a tiny share of the cases that the Justice Department has vetted under Section 5, Persily says it “gives a sense of how many dogs did not bark as a result of the threat of a denial of preclearance.”
Persily’s study also contains a great summary of the evidence Congress collected in the run-up to Section 5’s 2006 re-authorization (all told, it heard testimony from more than 90 witnesses and amassed some 15,000 pages of documents), though determined sleuths may want to consult the congressional record directly.
UPDATE, June 22, 2013: This post has been updated to include a reference to Gary May’s book, Bending Toward Justice: The Voting Rights Act and the Transformation of American Democracy. UPDATE, June 25, 2013: This post has been updated to include a reference to the Brennan Center for Justice’s “If Section 5 Falls” report.