EVELETH, Minn. – Workers in a call center on Minnesota’s Iron Range don headsets each day knowing their employer’s core business: Get Democrats elected. For years, prominent Democratic candidates and political groups have used the obscure center tucked among hills and pines to canvass and raise money from small donors. DFL organizations, state and national, have paid the phone bank’s current and former owners about $80 million over the last decade, campaign records show. The call center relocated to Eveleth in 2006 thanks in part to a $625,000 loan from a unique state agency called the Iron Range Resources and...