LOS ANGELES Few people turned out Saturday for a rally demanding amnesty for 11 million illegal immigrants, the latest sign of pro-immigrant groups' struggles to regain momentum after hundreds of thousands marched through the spring. Local bands played rock music, vendors offered chicken tacos and dozens of activists set up information booths in a downtown field. But by 5:30 p.m., more than an hour after the rally started, only 200 people had shown up. Most were organizers and journalists. Organizers, who had expected about 5,000 participants, downplayed the low turnout. They said more people could appear later and stressed that...