In the wake of the Sandy Hook school shooting, both President Obama and Sen. Diane Feinstein (D-CA) have unveiled proposals to ban assault weapons in the absence of the since-expired 1994 assault weapons ban. Although 44 percent of Americans favor banning assault weapons, according to the most recent Reason-Rupe poll, only 27 percent believe it would have helped avoid the Newtown tragedy. Nevertheless, belief that the expired federal ban could have prevented the shooting does bolster support for renewed efforts to ban assault weapons.

The Huffington Post reports Connecticut has a state assault weapons ban modeled after the now expired 1994 federal ban. Despite the ban, Connecticut law enforcement has reported Newtown shooter Adam Lanza's weapons were still legal in the state. Taken together, it seems unlikely that had the 1994 federal ban still been in effect it could have prevented the Newtown school shooting.

Among the 27 percent who thought the 1994 federal ban could have prevented the shooting, 72 percent were under the impression the law would have impeded Lanza from obtaining the firearms used. This helps explain why 77 percent of these Americans support renewed efforts to ban assault weapons nationally, but 18 percent still support private ownership of assault weapons. Those who believe the expired ban could have prevented the shooting are also significantly less likely to posses a firearm (30 percent), while 68 percent do not.

In contrast among those who do not believe the expired ban would have prevented the shooting, 66 percent believe Americans should be permitted to own assault weapons while 30 percent believe they should be prohibited. These households were significantly more likely to own a firearm (48 percent) while 47 percent do not.

To be clear, not all Americans who favor an assault weapons ban today think the previous ban could have prevented the Newtown tragedy. While 48 of assault weapons ban supporters believe the previous ban could have prevented the shooting, 45 percent disagree. Only 10 percent assault weapons ban opponents believe the expired ban could have prevented the shooting.

In sum, the perception the 1994 federal assault weapons ban could have prevented the Newtown massacre does explain a significant portion, although not all, of the support for a new ban.