Polls suggest that, after Newtown, the American public is increasingly open to measures such as a ban on assault weapons, which was in effect in the 1990s until it lapsed in 2004.

A CNN/ORC poll conducted after the shooting shows that a slight majority of Americans favor restrictions on guns. Conservative Democrats and some Republicans who have supported gun rights have said they are open to discussing gun control.

In a speech last Sunday night, Obama insisted inaction was not an option, especially when it comes to protecting children.

"We can't tolerate this anymore," the president said, alluding not only to Newtown but three other mass shootings over the past two years. "These tragedies must end. And to end them, we must change."