After Rand Paul received a suspicious package containing white powder at his home on Monday, the Kentucky Republican senator pointed the finger at an improbable alleged instigator: the 1980s pop star Richard Marx. “As a repeated target of violence, it is reprehensible that Twitter allows C-list celebrities to encourage violence against me and my family,” Paul said in a statement. “Just this weekend Richard Marx called for violence against me and now we receive this powder-filled letter.” After Paul said on Sunday he would not get vaccinated against Covid-19, Marx tweeted that if he ever met the senator’s erstwhile neighbor,...