The trial of a Nevada rancher, his two sons and another man accused of leading a 2014 armed standoff with federal agents in a dispute over land use begins this week. Stakes are high for federal prosecutors, who fell short of getting full convictions of other men who had guns during the dispute over a government round-up of Cliven Bundy’s cattle. In opening statements Tuesday prosecutors will accuse the 71-year-old Bundy, sons Ryan and Ammon Bundy, and co-defendant Ryan Payne of enlisting a self-styled militia to defy government authority.