Kamala Harris’s V.P. Pick Matters—but Not in the Way You Think

There are caveats, of course! Kopko and Devine conducted a separate analysis
focused specifically on the 2020 race and whether Harris or Pence had an effect.
It “suggested that Harris provided some advantage to the Democratic ticket with
regard to black women voters, but the effect was relatively small.” In a tight
election like 2020’s—and, presumably, 2024’s—even a small effect could be
important. Whether even the minuscule Kamala effect of 2020 is replicable is
anyone’s guess, but history suggests it won’t be. 

It does, however, raise the question
of whether Harris’s presence atop the ticket will further motivate those
voters. Kopko and Devine estimate that presidential candidates have roughly
three times as much influence on voter decisions as their running mates, so it
seems fair to wonder whether Harris topping the ticket will amplify the small
boost she provided four years ago. Maybe: Given that Black women are already the Democratic Party’s strongest constituency, there’s a limit to how many more votes they can provide. “Based
upon past data, [Harris] will likely garner an increase in support for Black
voters and Black women voters,” Kopko said. “It could be enough to matter in a
closely contested state.” 

Another caveat is that running
mates do make a difference in one notable way. A “vice presidential candidate can indirectly influence
voter behavior,” Kopko said. “Specifically, the selection of a running mate
provides information to voters, and that shapes perceptions of the presidential
candidate. For example, if a running mate is viewed as unqualified, that will
diminish perceptions of the presidential candidate (think Sarah Palin in
2008).… In practical terms, that’s where we see the selection of
a V.P. mattering most in terms of electoral effects—by shaping perceptions of the
presidential candidate.”