On Tuesday, Kamala Harris chose the next vice president of the United States: Governor Tim Walz of Minnesota. The question is, will this make voters more likely to elect Harris for president in November?
In short: Probably, but not by much and maybe not for the reasons you think.
Many people think that the vice presidential election will be a substitute for the election game. It’s a common mistake: Conventional wisdom has told us that a good one can boost a ticket by a few points — and a bad one can sink a campaign. But we’ve spent more than a decade studying vice-presidential candidates, and our research shows that voters’ opinions about a pair of candidates don’t have a direct impact on the presidential election.
Even if Walz proves to be quite popular with the American people – or quite unpopular, as Donald Trump’s partner, JD Vance, has so far proved – that alone will not change many votes. The truth is, voters choose the president of the United States who matters most. Yes, he also voted for the vice president, but that’s not that important to him.
Another common misconception is that a candidate’s spouse will “send” the state’s electoral votes to the presidential candidate. Of course, many of the finalists for the Harris ticket came from electorally competitive states — including Walz. But our research found there is very little evidence of “home country advantage” for running mates. On average, the effect is close to zero. This makes us skeptical that adding Walz to the ticket somehow guarantees that the Democrats will win Minnesota or other competitive Midwestern states.
Walz is not to be blamed for failing to deliver a significant electoral advantage — and neither is Vance, for that matter. Voters just don’t care about a pair of candidates. But the people at the bottom of the ticket can help in the margin, and for good reason: The choice of the vice president tells voters something important about the person running for president.
In Harris’s case, this “first presidential act” informed voters. Americans don’t know him as well as Joe Biden or Trump, and he has less time than most presidential candidates to make his case. Her choice will help voters evaluate their decision. It also helps them determine whether they are making responsible decisions, for the good of the country, or acting irresponsibly for short-term political gain. It tells people what core political values and priorities guide them.
By appointing Walz, Harris chose a qualified vice president for the job. The two-term governor previously served six terms in Congress, where he was the ranking member of the House Veterans Affairs Committee. Among Harris’ finalists, he is the only one who has served in both state and federal office. Walz’s combination of executive and foreign policy experience — plus 24 years of service in the Army National Guard — set him apart as “second in command” in the Harris White House.
Voters will reward Harris for choosing a credible vice president (and president). In fact, according to our research, this is the most important criterion of voters when evaluating the vice presidential election. This test meeting increases the opinion of the voters about the decision of the presidential candidates, who then get votes.
The opposite is also true. For example, in the 2008 election. Our analysis shows that voters who doubted Sarah Palin’s readiness for the presidency lost confidence in John McCain’s decisions and became less likely to vote for the Republican ticket. On the contrary, Barack Obama’s choice of Biden – a senator with decades more experience than he – increased confidence in his competence and votes for the Democratic ticket. If voters also believe Walz is White House material, he could help Harris win the election.
The choice could also benefit Democrats by ensuring the party’s progressive support. Harris was once considered the most liberal member of the Senate, and voters see him as more liberal than Biden. But during the 2020 presidential election, he was challenged from the left, especially on his record as prosecutor and attorney general, and Biden’s administration often faced resistance from more progressive elements of the Democratic Party.
Our research shows that Biden’s choice of Harris for vice president shifted his ideological perception to the left. Walz’s selection could also help shape Harris’ ideology, by convincing Democrats of his progressive bona fides without alienating more moderate voters. While Walz has governed Minnesota as a progressive, in Congress he represents a Republican-leaning district and is known as a relative moderate.
Voters will determine in November whether Harris made the right decision. For now, we can only rely on evidence from past elections to evaluate his choices. This information suggests that we do not expect Walz (or Vance) to be the deciding factor in the election. But if — as we suspect — voters see Walz as a credible potential vice president who can help Harris advance his legislative agenda, they could help him reach the Oval Office.
Christopher J. Devine is a professor of political science at the University of Dayton. Kyle C. Kopko is an adjunct professor of political science at Elizabethtown College. His most recent book is “Do Running Mates Matter? The Influence of Vice Presidential Candidates on Presidential Elections.
