“Former vice president Joe Biden is now the presumptive Democratic nominee for president — after a primary involving months of campaigning, 28 Democratic candidates and over $1 billion in ads," he writes. "Did any of that affect the result? Not much, our research suggests — but they weren’t meaningless.”
Democrats named Biden, Sanders and Warren as their top picks 18 months ago. What did the primaries change?
Peter K. Enns,