“As we’ve seen before, these horrific events occur and then the spotlight fades,” declared Doug McMillon, CEO of Walmart, America’s largest corporate employer. “We should not allow that to happen. Congress and the administration should act.” McMillon announced several moves that bring the spotlight back again.

While big companies have traditionally shied away from politically polarized issues, that’s changing recently, with Walmart taking a more aggressive position on gun control. The company announced this week that it would stop selling ammunition for military-style assault rifles and handguns, it will begin “respectfully requesting” that customers refrain from openly carrying weapons inside the company’s stores, and it will ask Congress to increase background checks and consider bringing back the U.S. assault-weapons ban.

McMillon had signaled earlier that the company would be making such moves in the aftermath of the mass shooting a month ago at a Walmart store in El Paso, where a gunman killed 22 people. Walmart is not only the largest U.S. retailer, with 4,000 stores, but also the largest seller of guns and ammo. For years, the company had been narrowing its selection of firearms, ending handgun sales in the 1990s (except for Alaska, where handgun sales will now end as well) and halting sales of assault rifles in 2015.

Given the Walmart’s roots in Arkansas and its omnipresence in rural America, the company has moved only gradually on the issue, even as overall public sentiment in the U.S. has increasingly favored greater gun control. But events have pushed the company into a position of leadership, especially given its scale. “Any decision that a company that is that big and that ubiquitous makes is going to please some people and upset others,” Aron Cramer, chief executive of BSR, a nonprofit group that advocates social responsibility in business, told the New York Times. “It is extremely hard not to take action when people are dying at one of your stores.” Walmart will continue to sell more traditional hunting firearms, but it estimates that its share of the U.S. ammunition market will fall to about 6%, down from 20% currently.

Despite Walmart’s huge small-town presence, the company has to consider the sentiments of its much more diverse stakeholders, who include urban and coastal customers as well as young people, all of whom tend to advocate stronger rules on gun safety. “The company is also trying to build its online business to compete with Amazon by recruiting younger engineers and developers, who are attracted to companies that profess social values that reflect their own,” the Times reported.

One of the trickiest things to enforce of Walmart’s new positions is its request that customers refrain from openly carrying guns in its stores, even in states where doing so is legal. Not long after Walmart’s announcement, Cincinnati-based Kroger, the largest U.S. supermarket chain, asked that its customers stop openly carrying guns into its stores and called for stronger background checks on gun buyers.

“The retailer will likely use new signage at entrances asking customers to leave weapons behind, but the retailer did not explain what store associates will do in the event a shopper shows up with a rifle slung over their shoulder or with a gun holstered on their hip,” the Cincinnati Enquirerreported.Thirty-one states allowthe open carrying of handguns without any license or permit, the result of dramatic changes in state laws over the past three decades to make such laws more lenient. Open carrying of long guns is permitted in 44 states.

Could the moves by such retail giants embolden other companies? "It's a positive step in the right direction," said Mike Dowling, CEO of of Northwell Health, New York State's largest health-care provider and private employer, told CNN. Dowling, who who has written about gun violence as a "public health crisis," likened Walmart's move to CVS' decision to stop selling tobacco products in 2014 out of a concern for public health.