HOMESTEAD, Florida — Former Rep. Beto O’Rourke (D-TX) told demonstrators and the assembled media outside the Homestead Temporary Shelter for Unaccompanied Children that migrant children from Central America “had no choice but to come here” because climate change had ravaged their countries. O’Rourke said that rising temperatures had created droughts, which made it more difficult for people to grow their own food. That, he said, forced them to undertake the arduous journey on foot to the U.S. border, and to cross illegally. O’Rourke was the fourth presidential candidate to visit the protest outside the facility, where thousands of teenagers, most...