Old Lyme — On Friday, Pink Floyd co-founder Roger Waters was sharing a stage with wounded veterans in Washington, D.C., crooning songs from the rock band's repertoire as part of a benefit concert to supports injured soldiers and their families.

Sunday afternoon, Waters was in Old Lyme, telling a full audience in the First Congregational Church of Old Lyme about his decision to dedicate his post-Pink Floyd life to advocating for boycotts of Israel.

"You have to choose your battlegrounds in your life," the former frontman said in a conversation with Israeli Haaretz columnist Gideon Levy as part of the 11th annual Tree of Life conference at the church. "For now, I'm pouring my energy into this particular question, and I'm making no apologies for that."

Waters, who is British, has emerged as one of the more well-known proponents of Boycott, Divest, and Sanction, a pro-Palestinian disinvestment campaign designed to penalize Israel.

"This is a movement that is spreading, and it's spreading very rapidly," Waters said.

While the idea is taking time to catch on among his colleagues in the music industry, he said he is optimistic.

"It is just beginning, those first flickering flames of solidarity are beginning to spread among some people, and when it goes off, it's going to spread like wildfire," he said.

Waters spoke with Levy, who profiled him in Haaretz in August, for just under an hour. Robert Gelbach, the co-chair of the New Haven chapter of Jewish Voice for Peace, moderated the conversation.

Waters said he began advocating for the B.D.S. movement when he was planning to play a concert in Israel in 2006.

He began to receive emails from people all over the world asking him to skip the country as a political statement.

"I realized there was a movement that I knew nothing about at the time," he said.

"I'm not talking about the Israeli people," he added. "I'm talking about the policies of this and many past Israeli governments in terms of the opression of the Palestinian people."

Levy praised non-Israelis like Waters who have dedicated their time to activism on behalf of Palestinians. He said few people in Israel display the same compassion.

"The denial (in Israel) is so deep, the ignorance is so wide," he said. "For ... Israelis like me, the only source of hope today is for people like Roger Waters."

Waters could have enjoyed his retirement without taking up the B.D.S. cause, he said, but "he decided to dedicate all of his time for a real struggle for justice," he said.

At the end of the talk, Waters read the lyrics to a song he said he wrote six months ago.

"When ... wise men concede that there's more than one way, more than one path, more than one book, more than one fisherman, more than one hook ... we will have done well if we're able to say ... that we never gave in, that we gave it all we could, so the kids could go fishing in crystal clear brooks."

m.shanahan@theday.com

Twitter: @martha_shan