The best vice presidential candidates typically offer something special that the top of the ticket lacks—offsetting a demographic weakness, for example, or counteracting a perceived character flaw. Donald Trump famously plucked Mike Pence from the political graveyard in Indiana to assuage the anxieties of evangelicals; Joe Biden tapped Kamala Harris, at least in part, in recognition of two of the Democratic Party’s most important coalitions. 

Of course, there is another, less openly discussed factor in the traditional veepstakes decision matrix: fundraising. The money race is particularly top-of-mind this cycle for wealthy Republicans, who are once again hemming and hawing over cutting big checks to Trump. Indeed, as my partner Tara Palmeri recently reported, the emerging consensus among Mar-a-Lago insiders is that Trump’s decision may come down to who can perform best with megadonors, either by getting them excited or by simply calming their nerves.