From left: Hinna Zeejah, 8, Taejah Goode, 10, Julia Stokes, 11, and Grant Fritz, 8, watch as the president signs gun-control proposals. (Nikki Kahn/The Washington Post)

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 Newton, Conn., which killed 20 children and six adults.

“I am very sad about the children who lost their lives,” wrote Taejah Goode, a 10-year-old from Georgia 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, a 7-year-old girl who was among those killed at Newtown, in his private study at the White House.

“Every time I look at that painting, I think about Grace and I think about the life that she lived and the life that lay ahead of her,” Obama said, adding that it reminds him that “we must act now . . . for all the Americans who are counting on us to keep them safe from harm.”

President Obama proposed expansive gun-control policies aimed at curbing gun violence. The Obama administration can implement about half of the proposals, but the others — arguably some of the more critical initiatives — will require congressional approval.

The prominence of children in Obama’s presentation prompted an immediate backlash from some conservatives. The right-leaning Drudge Report Web site 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.”

The child-focused news conference also 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 in a statement Wednesday. Some Democrats, including former House Democratic Caucus chairman John Larson (Conn.), called for the online spot to be taken down immediately; NRA President David Keene stood by the ad and said it “wasn’t about [Obama’s] daughters. It was about elites.”

The focus on children in the political arena is inevitable in the wake of a shooting tragedy that took place at an elementary school, several communications experts said. But they said there are key distinctions between the NRA ad and the White House’s use of children onstage — as well as the deployment of children by previous presidents and political candidates.

“Presidents always use props,” said George Edwards, a political scientist at Texas A&M University who studies presidential leadership and public opinion. “Children are a little more emotional, I suppose. 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?”

Whereas the White House event focused on children from across the country who had written letters to Obama, the NRA ad breached the “zone of privacy” usually given to the president’s children, said Brendan J. Doherty, an associate professor of political science at the U.S. Naval Academy and the author of “The Rise of the President’s Permanent Campaign.”

“There’s a long-standing tradition of keeping the underage children of the president out of the political to-and-fro,” Doherty said. “The ad by the NRA does violate that tradition in a way that has stirred up a lot of attention across the ideological spectrum.”

But he added: “I imagine the NRA would say if it’s fair game for the president to invoke children to make his point, then it is for them as well.”

The deployment of children at official political events is nothing new. George W. Bush held the ceremony for his 2002 signing of the “No Child Left Behind” bill at a high school in Hamilton, Ohio. Rep. Nancy Pelosi (D-Calif.) was famously surrounded by children in the House chamber when she was sworn in as the first female House speaker in 2007.

Candidates for political office have long used children in their campaign ads, a tactic that has been known to backfire on occasion: Former congressman Ben Quayle (R-Ariz.) got in hot water in 2010 for a campaign mailer that featured him playing with two little girls who were not his daughters. (The Quayle campaign later explained that they were the candidate’s nieces.)

Where Obama’s Wednesday event differs is the fact that the children who were included had written to the White House in favor of stricter gun regulations, political 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 who is an expert in political stagecraft. “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 on the stage with the president — and that might be what’s new and different here.”

In that sense, Wednesday’s gun-control news conference bore echoes of Obama’s 2010 signing of the Affordable Care Act health-care law. At that event, the president was accompanied by Marcelas Owens, an 11-year-old boy who became a reform advocate after the death of his uninsured mother.

But Edwards said the White House’s use of children is unlikely to have much impact on the overall debate, particularly as it moves to Capitol Hill.

“Presidents almost never change people’s minds about policies,” he said. “Events do. Tragedies do. And it’s the tragedies, recently, that have softened people up.”