For four decades, the National Rifle Association has pumped millions of dollars into federal elections, supporting both Republican and Democratic candidates who voted in accordance with the gun group’s strict view of the Second Amendment. That era is over. During the last federal election cycle, in 2014, the gun group’s spending on behalf of Democrats dwindled to virtually nothing, even as its overall election-related spending soared to more than $32 million, an analysis by the Daily News and The Trace found.