The Sandy Hook massacre, which took place one month after the 2012 election, upended Obama’s second-term legislative agenda. The national trauma resulting from the murders of 20 small children was so profound that Obama reasonably concluded this was not a time for caution and calculation. In January 2013, Obama proposed a long list of measures, including bans on assault weapons ban and armor-piercing bullets and a limit on the size of magazines.

And yet he began his gun control push from a position of political weakness. He had not campaigned on gun control, let alone a specific set of gun control proposals. He couldn’t influence lawmakers with clear evidence of red- and purple-state voters who were dedicated to his proposals. No broad-based gun control movement was in place to apply grassroots pressure (despite the efforts of billionaire Michael Bloomberg to build one with his Everytown for Gun Safety organization).

Meanwhile, the National Rifle Association had cultivated for decades a movement of single-issue voters, fostering a cultural identity around gun ownership that fortifies its legal and constitutional arguments. We now know that the NRA leadership was internally conflicted about how to respond to the unique horror that was Sandy Hook, but the ultimate decision to continue its unwavering defiance against any gun restrictions worked perfectly, and kept most Republicans (and a few Democrats) in line.