Is Biden Beatable?

For months, the Democratic presidential primary has been between Joe Biden and Bernie Sanders.
According to Politico, that primary is now over.
Many Democratic operatives say that Biden and Sanders are suddenly within reach in a race that has broken wide open.
“Bernie and Biden were largely living off of inertia,” said Colin Strother, a veteran Democratic strategist.
Now, Strother says, voters are becoming aware that “other [candidates], they have a lot of other things to offer.