Warren, a Massachusetts senator and leading progressive, has become an unlikely confidant and adviser to Biden, the presumptive Democratic presidential nominee. Warren, a Massachusetts senator and leading progressive, has become an unlikely confidant and adviser to Biden, the presumptive Democratic presidential nominee. Those forums have provided opportunities for Warren to make a case on top policy issues to Biden, who ran a more centrist primary campaign. Her presidential campaign didnt go particularly well, Reed said. But Warren has lately become a visible face of the Biden campaign.