It turns out you can govern in 140 characters. Social media is often accused of coarsening our public discourse and of making us stupid. But some innovative public leaders are taking to their keyboards and finding that the payoff is a direct and personal connection with their communities.

To understand how statecraft by Twitter works, I spoke to three avid practitioners, who are spread around the globe and work at different levels of government: Carl Bildt, the foreign minister of Sweden; Michael McFaul, the U.S. ambassador to Russia; and Naheed Nenshi, the mayor of Calgary, Alberta.

Bildt is a veteran blogger, but he was dubious about Web 2.0, as the social-media revolution is sometimes called. “I was rather skeptical on Twitter,” he told me. “I thought, ‘What can you say in 140 characters?’”

But Bildt, who has more than 116,000 followers , soon found Twitter to be “very useful” and also “fun.”

“As a matter of fact, you can say something in 140 characters,” he said. “The restriction isn’t as absolute as I had thought.”