CHICAGO — Score one for No. 2.

Burger King — always the bridesmaid, never the bride — delivered a rare jolt of publicity for itself by calling for a “ceasefire” with historic archrival McDonald’s in full-page ads Wednesday in the Chicago Tribune and The New York Times.

In “an open letter,” Burger King implored McDonald’s to collaborate on creating the stuff of fast food junkies’ dreams: the McWhopper. The idea was to come together in Atlanta — a midpoint between Burger King’s Miami headquarters and McDonald’s, based in suburban Chicago — and make the sandwich at a pop-up restaurant for one day in promotion of the global Peace Day on Sept. 21.

In a Facebook post, McDonald’s CEO Steve Easterbrook said: “We love the intention but think our two brands could do something bigger to make a difference.”

Commence the social media backlash from people who apparently really liked the McWhopper idea.

“It’s a great move by Burger King. It’s a win-win for them. You can’t lose,” said Dan Azzaro, senior lecturer in the advertising program at DePaul University College of Communication. “It’s all about ‘How do you agitate the giant?’”

The “burger war” between McDonald’s and Burger King is a thing of the past, Azzaro said, but Burger King’s McWhopper proposal relies on that very premise. In reality, McDonald’s is more challenged these days by fast casual restaurants like Chipotle and Panera Bread, he said.

“We’re talking about Burger King. And how often do we do that except for when that creepy King rolls around?” Azzaro said.