The move by the White House on Wednesday to feature four children at President Obama's gun-control news conference set into motion a new debate over the role of young people on the political stage.

In unveiling his proposals to address gun violence, Obama was accompanied by four children who had written to him in favor of stricter firearms laws in the wake of the Dec. 14 massacre at Sandy Hook Elementary School in Newtown, Conn., which killed 20 children and six adults.

"I am very sad about the children who lost their lives," wrote Taejah Goode, 10, who attended Wednesday's event. "So, I thought I would write to you to STOP gun violence."

Obama also noted that he has hung a painting made by Grace McDonnell, 7, who was among those killed at Newtown, in his private study.

The prominence of children prompted a backlash from some conservatives. The right-leaning Drudge Report website ran a photo of Obama high-fiving one of the children gathered at the White House along with the headline "Let's Play Take the Guns."

It came one day after the National Rifle Association invoked the president's daughters in a provocative Web video, a move that White House press secretary Jay Carney criticized as "repugnant and cowardly."

"Most Americans agree that a president's children should not be used as pawns in a political fight," Carney said. Some Democrats called for the spot to be taken down, but NRA President David Keene said the ad "wasn't about [Obama's] daughters. It was about elites."

The focus on children is inevitable in the wake of a shooting that took place at an elementary school, experts said. But they said there are key distinctions between the NRA ad and Obama's use of children onstage.

"Presidents always use props," said George Edwards, a political scientist at Texas A&M University. "But it is children who're getting slaughtered in these schools, so who would you bring in if you wanted to talk about children being slaughtered in schools?"

The NRA ad breached the "zone of privacy" usually given to the president's children, said Brendan Doherty, an associate professor at the U.S. Naval Academy. "There's a long-standing tradition of keeping the underage children of the president out of the political to-and-fro."

The deployment of children at political events is nothing new. George W. Bush held the ceremony for his "No Child Left Behind" signing at a high school in Hamilton, Ohio.

Where Obama's event differs is the fact that the children had written in favor of stricter gun regulations, analysts said. "Certainly there have been children at presidential press photo ops in years past, but usually more in a decorative way, not in a policy way," said Alan Schroeder, an associate professor of journalism at Northeastern University. "I think what's interesting here is that the children were a reflection, really, of the larger issue -- that there was a political component to the children's presence ... -- and that might be what's new and different here."