WASHINGTON (AP) — Michelle Obama is speaking out about the toll that gun violence is taking on young people, in a shift that shows the first lady's willingness to tackle new and polarizing issues as she shapes her second term. A meeting with high school students from a poor, gang-infested neighborhood in Chicago, her hometown, led Mrs. Obama to put a new spin on the stalled legislative debate over whether to ban firearms or impose new background checks on people who want to buy guns. A mother to a teen and a tween, Mrs. Obama argues that the debate also...