On March 14, Mattituck businessman Greg Williams announced he would run as a Republican for the Suffolk County Legislature. Three days later, at 8:42 a.m., Mr. Williams received a text message from William Mann, an employee of the Suffolk County Board of Elections. While largely incomprehensible, the text contained what Mr. Williams saw as a direct threat. He provided the text to The Suffolk Times. It read: “We need to talk you [expletive] on me as a problem and there’s a problem I’m going to challenge every [expletive] petition signature you get I didn’t want to do this on a...