Updated on April 5 at 1:42 p.m. ET (see below)

While attention is focused on the U.S. Senate, which could begin voting as early as next month on gun control legislation, some state lawmakers are trying to move in the opposite direction.

Bills to nullify any gun control measures that Congress enacts have been introduced in at least 37 states since the beginning of the year, according to an analysis using Scout, Sunlight's legislative alert system. To browse the list and click through to the text of the bills, click here.