Birthright israel's free trips to the country – paid for by Jewish philanthropists eager to foster ties to Israel and Judaism – don't only provide safe passage to fervent Zionists. The program has also attracted members of the pro-Palestinian International Solidarity Movement who fit the requirements for participation: They are Jewish, 18 to 26, and have never been on an organized tour of the country. "It's a free ticket," explained ISM cofounder Adam Shapiro, who informed student activists at November's Palestine Solidarity Movement conference at Ohio State University of the birthright trips. He said he knows personally at least five...