Poli-Sci Perspective is a weekly Wonkblog feature in which Georgetown University's Dan Hopkins and George Washington University's Danny Hayes and John Sides offer an empirical perspective on the issues dominating Washington. In this edition, Hayes looks at how media interest in gun control has fallen off since the Senate bill failed. For past posts in the series, head here.

Seven months ago, Adam Lanza blasted his way into a first-grade classroom at Sandy Hook Elementary School, murdering 20 children and six staff members before turning the gun on himself.

The massacre in Newtown, Conn., set off a furious debate, prompting an unprecedented amount of media attention on America’s gun laws. But the press’s declining interest in gun control in recent months illustrates just how hard it is for advocates to keep a story alive once Washington stops fighting over it.

As I’ve written previously, media coverage in the wake of major shootings tends to follow what’s known as the “issue attention cycle.” Gun control stories spike immediately afterward but fall off the agenda as other events and issues emerge to occupy the media’s interest. This happened after the 2007 Virginia Tech massacre and, the 2011 shooting of Gabby Giffords in Tucson, and the 2012 attack in an Aurora, Co. movie theater.

Although Newtown appeared to defy that pattern in the two months after the shooting, it’s now clear that the issue attention cycle simply took longer to assert itself.

The graph below displays the number of stories that included the phrase “gun control” for each week during the last seven months. The data come from a search of more than 500 outlets in the U.S. News & Wires database in Lexis-Nexis. The chart begins with the seven days before the Dec. 14, 2012 shooting, and ends with data collected Friday.

Gun control coverage spiked with the shooting, and then again in January when President Obama announced 23 executive actions designed to curb gun violence. Throughout the next two months, however, coverage dropped significantly. By the week of March 15, gun control stories had dropped by two-thirds compared to the January peak.

As momentum for a Senate vote picked up, gun control surged back into the news. The week of the April 17 vote, there were 1,584 stories in the Lexis-Nexis database.

But when the Manchin-Toomey background check bill failed to surmount a filibuster, the media’s attention span began nearing its end. A month after the bill died, there were 465 gun control stories. And just last week, the number was down to 371. That was still twice as many as the week before Sandy Hook, but nothing like what front-burner political issues tend to receive. (Even last week there were 532 stories about Edward Snowden, owner of the Guinness record for the world’s longest layover.)

The decline of media coverage after the demise of the Senate bill underscores a point that’s worth repeating about the factors that tend to drive journalists’ attention to policy debates.

The inherent newsworthiness of an event – such as the nearly unfathomable slaughter of 20 first-graders – is not enough to sustain the media’s interest. If it were, we’d still be reading front-page stories about Newtown: Nothing that has happened in Washington in the last seven months has been more horrifying, tragic, or gripping than what took place on that Friday at Sandy Hook Elementary.

Neither can the crusade of an activist, no matter how compelling, achieve what a good dust-up on Capitol Hill can. It’s possible that Giffords’ weeklong national tour earlier this month, designed to (re)mobilize support for expanded background checks, arrested the decline of gun control coverage. But despite a photo-op of the former congresswoman firing a pistol at a Las Vegas range – about as close as you can get to journalistic catnip – there is no evidence that it regenerated the media’s interest.

The media’s interest in policy debates generally lasts only as long as politicians are willing to spar in front of the cameras. And although Democrats have pledged to continue pursuing stricter gun laws, the prospects for meaningful legislation – and thus a meaningful battle – appear uncertain.

Gun control advocates have by no means given up. Giffords, New York City Mayor Michael Bloomberg, and a coalition of allies are continuing their efforts to overcome Republican and NRA opposition to stricter gun laws.

But in the near term, they’re unlikely to get much help from the media. Once the Senate gun control bill died in April, so did the story.