The failure of Congress to advance gun legislation in the wake of the deadliest mass shooting in modern American history has once again raised questions about the influence of the National Rifle Association, the powerful gun lobbying force that opposes reform.

The NRA exerts its influence by pressuring lawmakers to adhere to its strict interpretation of the Second Amendment. Those that don’t meet this test get failing grades from the organization, and face potential backlash at the polls from its claimed five million members. The NRA also spends a great deal of money — more now than ever before — to elect, or defeat, lawmakers.

In May, The Trace and the New York Daily News examined the gun group’s election spending over the last three election cycles. The focus was on independent expenditures, or cash spent on ads and other media, separate from what is given directly to candidates.

After 2010, when the Supreme Court lifted the cap on election spending by outside groups, the NRA’s expenditures increased dramatically. By 2014, the group had disbursed over $56 million to influence federal elections, almost all of it in the service of electing Republicans.

Slate has put together a widget that allows readers to see how the federal lawmakers who represent them have been affected by NRA spending. The data goes back to 1990, and accounts for the organization’s total spending per election cycle, not just independent expenditures.

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On July 5, Congress goes back into session, and the NRA will encounter advocates of tougher gun laws eager for a fight. The gun group will also have its eye on the November elections. For the first time in a decade, Republicans have majorities in both chambers going into a national election, which puts the NRA in the unique position of playing defense. In the coming months, the organization’s spending will ramp up, and if the trend continues along the lines of the last three election cycles, it will reach unprecedented levels.

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