On picket lines around the country, auto workers aren’t just demanding higher wages. They want to get back their once-sacred retirement pensions. While United Auto Workers members who were hired prior to the 2008 financial crisis have pensions, those brought on since have received 401(k) plans instead. The union is demanding the auto companies provide pensions for new employees and those who currently lack them. Ford Motor Co., General Motors Co. and Stellantis NV are determined to consign pensions to the past even as striking UAW members are just as keen to revive them. The fight has resonance well beyond the auto industry: With inflation persisting as the U.S. enters another fraught presidential election cycle, the plight of the middle class — and the financial condition of millions of retirees — is front and center.