The nation’s school boards are asking President Joe Biden for federal assistance to investigate and stop a growing number of threats made against their members. The National School Boards Association sent a letter to Biden Thursday, describing members being put on watch lists and threatened in person, online and through the mail in what it says amounts to domestic terrorism. The association wants the FBI and other federal agencies to work with local police and schools to monitor threat levels and assess the risk to students, school officials and school buildings. Attendees stirred up over mask mandates and instruction on racism have disrupted meetings around the country.