PHILADELPHIA—Seeking to make her case to the nation’s voters as she accepted her party’s presidential nomination Thursday night, Hillary Clinton reportedly began her headlining address at the Democratic National Convention by holding her infant grandson, Aidan, upside down by his ankle and firmly intoning the word “Family” in front of the assembled crowd. “Family. Grandson. Our future,” said Clinton, dangling the sobbing, squirming 6-week-old child above her head and slowly pivoting from one side to the other at the lectern so the entire audience could see him. “Mothers. Values. Important. Together.” Clinton then reportedly nodded, uttered the word “Finished,” and placed the bawling infant in a plastic bin held by a campaign aide before continuing on with her speech.