As Nancy Watzman has detailed elsewhere in this series today, much of the activity in the gun debate happens at the state level, rather than in Congress. That's why the Sunlight Foundation created the chart below. It provides a state-by-state breakdown of contributions that interest groups on both sides have given to candidates for federal and state office.
The chart is powered by Sunlight's Influence Explorer, which compiles campaign contribution data from the Center for Responsive Politics and the National Institute on Money in State Politics. It gives a complete picture through the 2012 elections; data from some of the 2013 contests described in today's stories has not been completely entered yet.
Political Party Time: Sandy Hook hasn't dampened pols' enthusiasm for gun fundraisers.
To see independent expenditures -- those made in support of, but not directly to federal candidates -- for the 2014 cycle, use the Sunlight Foundation's Real-Time FEC tracker. Here's an example of a search for outside campaign spending by the National Rifle Association. Caveat: Many expenditures that seem campaign-related to a layperson's eye are not considered as such by the Federal Election Commission and so don't have to be disclosed. That's why the Sunlight Foundation has created Political Ad Sleuth which uses Federal Communications Commission data to allow users to search for ad buys in the 50 major TV markets. Here's an example of a search for buys since Jan. 1 by Mayors against Illegal Guns.
You can also follow the issue through Congress, the federal regulatory system, the courts and the state legislatures by signing up for an account on Scout.