Matthew Yglesias: “The selection of a vice president is one of the most substantively important decisions a president makes. You want to draw from the broadest possible talent pool, and making the selection early is antithetical to that on a whole number of levels — most importantly because a lot of key talent won’t necessarily be willing to embrace your cause so early. (Including the rest of the field running for the nomination.)”
“Locking yourself into the relatively narrow category of ‘politicians who are willing to make an early Joe Biden endorsement’ ends up excluding a huge number of people, could prove tactically disadvantageous during a general election, and would be a blown opportunity to improve governance if Biden won.”