Starting on September 1st, the US Code added a new Title. Sections concerning the voting and elections that were previously found in titles 2 and 42 are now being moved to a new Title 52. The idea behind the addition is to both simplify the existing sections of 2 and 42 and make a more coherent Title that pertains only to voting and elections.
For online versions of the code, you can now cite Title 52. For print editions, the change will take effect with the publication of supplement II of the 2012 edition.
For more background on the change and resources to check on during the transition, visit the USC webpage that discusses the update in more depth.