Could efforts like this become a victim of their own success?
It's something to watch out for, said one of the veterans of long efforts to build such cooperation, Rabbi James Rudin. He's the senior interreligious adviser to the American Jewish Committee.
Rabbi Rudin spoke Feb. 11-12 at Rodef Shalom Congregation in forums that marked this year's he 50th anniversary of Nostra Aetate, the landmark document of the Second Vatican Council that repudiated the long legacy of teachings of contempt against Jews.
The effort to pass that document, which involved lots of behind-the-scenes maneuvering at the Vatican, "was difficult, it was important, (and) all of its promise has not yet been fulfilled," said Rabbi Rudin.
But those were largely tactical challenges, he said. Those who want to continue its legacy need to be vigilant about sweeping changes of a more strategic nature.
Rabbi Rudin said when he speaks to younger generations, they know little about Nostra Aetate or the history of Catholic-Jewish relations, which are largely positive now. It's easy to see how these groups could get complacent about interfaith dialogue.
"Will it be marginalized, ... will it be trivialized?" he asked.
He paid tribute to the popes, rabbis and other leaders of the generation that brought about Nostra Aetate. But he said that, like World War II's "Greatest Generation," they are passing into history.
"I call them the Moses generation. They are the ones who set in motion why we are here today," he said, employing biblical metaphors. "We're the Joshua generation. It's up to us to cross over and bring fulfillment to all they labored for."
But there are huge challenges -- demographic and geographic shifts in which most of the world's Christians are no longer in Europe or North America but in the Global South, even as the center of Jewish population concentrates in Israel.
"The problem for Jews is precisely the areas of greatest Christian growth are precisely the areas that ... there's no viable Jewish community for these growing Christian communities to relate to," he said.
"This is irreversible, and it's going to affect Christian-Jewish relations for the next century," he said. "We have Christians growing up where there's no vital Jewish population."
Then there's technology. People can form virtual churches, synagogues and study circles online rather than in "big box" sanctuaries, even beautiful ones. "They don't need rabbis, priests or pastors," he said. That means they won't be relying as much on the kind of leaders who worked toward Nostra Aetate, but it also means they can launch interfaith efforts online, without waiting for leaders.
On another note of grand historical trends, he cited recent news that Spain and Portugal have decided to offer citizenship to descendants of Jews expelled from their countries half a millennium ago.
"We who are historians (realize) you never say never, because you never know," he said.