Elizabeth Warren is best known as a liberal firebrand, but the 2020 Democrat was a registered Republican well into her 40s. The Massachusetts senator's affiliation with the GOP until 1996 when she was 47, documented by Pennsylvania and Massachusetts voting records, was dredged up this week by actress and Bernie Sanders fan Susan Sarandon. The film and small-screen star alluded to the Massachusetts senator's prior party allegiance while introducing Sanders in Iowa, despite the Vermont senator's campaign urging surrogates not to criticize fellow presidential candidates. “He is not someone who used to be a Republican,” Sarandon said of the socialist,...