A series of "Starbucks Appreciation Days" supporting the coffee chain's policy of letting customers openly carry guns seem to have backfired. In an open letter published yesterday, company CEO Howard Schultz said Starbucks had been pushed into one of America's biggest cultural battles — and asked visitors in the US to stop bringing their guns into stores. "We are respectfully requesting that customers no longer bring firearms into our stores or outdoor seating areas — even in states where 'open carry' is permitted — unless they are authorized law enforcement personnel," he wrote.

For years, Starbucks has held out against gun control advocates who asked it to ban firearms in its stores, something it's allowed to do even in some states with "open carry" laws. After a gun victims' support group called for a boycott in early 2012 because of its policy, supporters of firearm ownership organized a "Starbucks Appreciation Day," buying coffee and food while packing pistols (in states where it was legal to do so.) Starbucks, meanwhile, consistently said that it would follow local laws about openly carrying guns.

While the event was continued this year, the Sandy Hook shooting in late 2012 cast a pall over it. Starbucks made no move to stop either pro- or anti-gun advocates from visiting its stores, but it closed a branch in Newtown out of respect for "everything the community has been through." Elsewhere, customers celebrated once again with pistols and, in at least one case, an assault rifle. Now, Schultz tells Businessweek that the decision to stop welcoming guns was made over the course of months, saying it was not related to this week's shooting at Washington, DC's Navy Yard.

Schultz still isn't making a statement on open carry laws, but he said the appreciation days had been taking their toll on employees and other customers, especially given an "increasingly uncivil" debate.

Pro-gun activists have used our stores as a political stage for media events misleadingly called "Starbucks Appreciation Days" that disingenuously portray Starbucks as a champion of "open carry." To be clear: we do not want these events in our stores. Some anti-gun activists have also played a role in ratcheting up the rhetoric and friction, including soliciting and confronting our customers and partners.

That doesn't mean Starbucks is outright banning guns. While the company is politely asking people not to bring them into coffee shops (or at least not carry them openly), it's instructed employees not to confront anyone who does bring one in, both because of the potential danger and because "we want to give responsible gun owners the chance to respect our request." Instead, Starbucks will ask people to leave their guns behind through "external media," likely a posted sign. Schultz has urged advocates on any side to take their battles to Congress, but his final point is likely to annoy those who see "a good guy with a gun" as a source of safety: "The presence of a weapon in our stores is unsettling and upsetting for many of our customers."