MIAMI, Florida — The Florida teenager accused of carrying out the deadliest mass shooting at a high school in US history was scheduled to appear in court on Tuesday as a long-simmering national debate rages on between proponents of gun rights and advocates of firearms controls. Nikolas Cruz, 19, was expected to be in a Broward County criminal court for a hearing on obtaining evidence from him, almost two weeks after 17 people were shot and killed at Marjory Stoneman Douglas High School in Parkland, Florida, an affluent suburb of Fort Lauderdale. The 14 students and three adult educators killed were shot with a semiautomatic AR-15-