LAS VEGAS — A conference for a far-right sheriffs group this week drew a parade of felons, disgraced politicians, election deniers, conspiracy theorists and, in the end, a few sheriffs. The Constitutional Sheriffs and Peace Officers Association, or CSPOA, met in Las Vegas’ Ahern Luxury Boutique Hotel conference center to publicly counter reports of extremism within the group and set a course for the coming election — one that involves sheriffs’ investigating what they claim, despite a lack of evidence, is rampant voter fraud. The group sees sheriffs as the highest authority in the U.S., more powerful than the federal...