Last week, we looked at a chart showing how the number of gun businesses in a senator's state affected their vote on gun control. Today, we look at another chart that tells the story of the gun debate.

The Pew Research Center is out with a new report that shows -- via social media statistics -- a good approximation of why the gun control push failed.

The chart below compares pro-gun control and anti-gun control messages on Twitter over the course of the gun debate, along with total tweets on the issue for the same period.

While the chart above doesn't show it, pro-gun control messages were winning big on Twitter shortly after the massacre at Newtown -- 64 percent to 21 percent. That faded quickly and the two sides were pretty even until the very end, when pro-gun control messages spiked again. Of course, by that time, the legislation was already doomed.

Gun-control advocates -- led by President Obama -- often pointed out that 90 percent of Americans supported increased background checks, but that number wasn't translating to the social media debate. Gun control supporters quite simply weren't able to keep their side mobilized and active, which is perhaps a good indicator of the superior motivation on the other side of the issue.

The second half of the chart shows that, after Obama introduced his gun legislation, interest in the issue was very high but dropped precipitously. It spiked again before Obama introduced his gun control proposal, but then receded again.

True, it's hard to keep the American public engaged for months on-end -- regardless of the issue -- but the months of February and March, with little movement on the bill and with Newtown fading from memory, might have been what did in the legislation.

The lack of immediacy was quite simply gone, and pro-gun control forces couldn't keep the momentum going in the intervening months.