As Vice President Kamala Harris embarks on her campaign for the White House, she faces a daunting historical challenge. Since 1836, only one sitting vice president, George H.W. Bush in 1988, has successfully been elected president. The odds are steep, with figures like Richard Nixon in 1960, Hubert Humphrey in 1968, and Al Gore in 2000 all having tried and failed under similar circumstances.

These past attempts were marred by close elections influenced by various issues, such as war, scandal, and public perception. However, two critical factors were often at play: the popularity of the incumbent president and the relationship between the president and vice president. Princeton University professor Julian Zelizer notes, “If the president is well-liked, that can be a significant boost for the vice president. And a strong working relationship between the two is crucial.”

In 1988, Bush benefited from a solid economy, the easing of Cold War tensions, and an endorsement from a popular president, Ronald Reagan, despite the shadow of the Iran-Contra scandal. Reagan’s public support helped Bush secure a decisive victory against Democrat Michael Dukakis. In contrast, Al Gore, despite running during a period of economic prosperity under Bill Clinton, distanced himself from the president due to the Monica Lewinsky scandal. This separation is often cited as a key factor in Gore’s narrow loss to George W. Bush.

Nixon, too, struggled to leverage his association with the popular Dwight Eisenhower in 1960, partly due to a complicated relationship between the two men. Nixon’s reluctance to fully embrace Eisenhower’s support may have cost him crucial votes against John F. Kennedy.

As Harris begins her campaign, she will need to navigate these historical challenges. President Joe Biden’s support, his approval ratings, and their working relationship will be significant factors in her bid for the presidency. Biden, who also served as vice president before becoming president, has pledged his full support for Harris, which could be a crucial asset in the months ahead.