We know how Biden has approached this in the past. In 2015, when he considered, then abandoned a run for president, he had talks with Senator Elizabeth Warren of Massachusetts exploring the possibilities of a joint ticket.
This time round, Biden has an impressive shortlist to choose from. David Weigel of the Washington Post has set out the three tests Biden has to consider in selecting his running mate.
The excite-the-base test.
Biden starts his vice presidential selection process with a lead in the polls. But he struggles with younger voters and Latino voters, who heavily supported Bernie Sanders in the primaries, and he was the nominee least trusted by many left-wing progressive groups. Weigel writes “Biden performed best in the primaries with suburban whites and black voters of all kinds and has not run as strongly as Barack Obama did with the party's most liberal voters.” That’s why front runners must be black women like Sen Kamala Harris of California and Georgia’s Stacey Abrams and Elizabeth Warren who is best placed to unite the left behind Biden.
The ready-to-serve test.
When James Corden asked him about a running mate on “The Late Late Show,” Biden said he wanted a woman “capable of being president of the United States tomorrow.” If Biden wins in November he will be the fifth Vice President in my lifetime to go on to become President, after Richard Nixon, Lyndon B Johnson, Gerald Ford and George H W Bush. Americans could be electing the next two Presidents when they vote in November.
The do-no-harm test.
This is when it gets more complicated thanks to the vagaries of the US political system. Biden is under pressure to consider also the knock on effect of picking a candidate whose election would allow the Republicans to nominate a replacement for the ensuing vacancy.
Finally there is a wildcard that could still be played. A Pittsburgh TV station recently asked about Michelle Obama and Biden said he'd “take her in a heartbeat,” though the former first lady consistently rules it out. Can Michelle Obama meet these three tests and help Biden over the line in November? ‘Yes she can’. Will she? Probably not.