Looming Question for Putin Opponents: Can You Change Russia From Jail?
Mr. Gudkov went into exile after what he described as “credible threats” that a criminal case against him would result in jail time. He said he had encouraged Mr. Yashin, a longtime friend, to go into exile as well.

Yevgenia M. Albats, a journalist and friend of Mr. Yashin who also decided to stay, took the opposite view, saying it was impossible to engage in politics seriously from abroad.

“You cannot be a Russian politician in New York, in Manhattan,” Ms. Albats said in a phone interview from Moscow. “You cannot call yourself a Russian politician and be in London.” Still, she conceded, “The risks are very high and they are getting higher.”

Mr. Yashin acknowledged as much in the YouTube interview posted shortly before his arrest, with the Russian journalist Yuri Dud. “I understand that each day could be my last one as a free man,” he said.

He later wrote on social media that he believed it was his clear refusal to leave, expressed in that interview, that resulted in his arrest.