But will RFK Jr. hurt Trump or Biden more?
To find an answer, I’ll analyze the presidential elections throughout history when there was a viable third party.
My research reveals that when a third party or independent presidential candidate challenges the two-party system when an incumbent president is on the ballot, the incumbent president wins half the time.
ALSO READ: Alexandria Ocasio-Cortez takes 'victory lap' after making GOP see red over tiny green pins
Third party and independent candidates do most of their damage when there isn’t an incumbent running for reelection. The party in control of the White House loses two out of three races in these “open seat” situations.
However, that’s not the whole story.
Additional research of mine shows that independent candidates and third parties tend to pull away votes from challengers, even when those challengers are successful. Because third parties and independents split the anti-establishment vote, challengers such as Trump should worry more about third party and independent candidates — RFK Jr. most notably — than Biden during the 2024 election.
Joe Biden answers a question as then-President Donald Trump listens during the second and final presidential debate at Belmont University on October 22, 2020, in Nashville, Tenn. (Photo by Morry Gash-Pool/Getty Images)
There are four cases (George H. W. Bush, Jimmy Carter, William Howard Taft and Benjamin Harrison) where an incumbent lost after facing a credible independent or third-party challenger who garnered some minimal degree of national attention.
There are just as many cases, four, where a president faced a third party or independent, and prevailed: Bill Clinton, Harry Truman, Calvin Coolidge, and Andrew Jackson.
Independents and third parties do the most damage in races where there is not an incumbent on the ticket.
ALSO READ: A neuroscientist reveals how Trump and Biden's cognitive impairments are different
Of those nine cases, six of those helped cause the party in power to lose the White House (2016, 2000, 1968, 1860, 1852, 1848). In only three of these scenarios did the party in power maintain control of the White House — all during the years before the modern two-party system.
But there’s an additional factor both Democrats and Republicans should consider.
My prior research shows that when third parties run presidential candidates, they tend to weaken the challenger’s performance, even when the challenger manages to win.
Polling evidence shows that in 1992, independent H. Ross Perot’s temporary exit from the presidential race in July dramatically boosted Clinton’s position.
Then-President George H.W. Bush (R) has his turn to answer questions during the 1992 debate held at the University of Richmond. Other candidates are Ross Perot (I) and then-Arkansas Gov. Bill Clinton (D). (Photo by Mark Reinstein/Corbis via Getty Images)
Perot’s return to the race in October cut significantly into Clinton’s lead, making Clinton’s eventual win over Bush much more narrow than it otherwise would have been.
Similar research by Steve Kornacki, writing for Salon (now with NBC/MSNBC), shows that independent presidential candidate John Anderson’s effort did not cost Carter the election — and may have cut into Reagan’s popular vote totals.
George Wallace’s independent presence in the 1968 presidential election cut deeply into Republican Richard Nixon’s electoral vote totals in the South and helped Democratic candidate Hubert Humphrey, which may have been the Alabama governor’s goal all along. Nixon certainly worried about the chance of this happening.
ALSO READ: Lauren Boebert’s high school has canceled the congresswoman
In conclusion, there’s no guarantee that the RFK Jr. entrance into the election will benefit Trump.
Despite Kennedy’s former association with the Democratic Party and some liberal leanings, particularly concerning the environment, his tough-on-immigrant border policies and anti-vaccine theories in particular may well appeal more to like-minded conservatives and center-right independents who can’t stomach the thought of a second Trump presidency — or another four years of Biden.
If anything, Trump may well have more to worry about than Biden, as these independents and third-party candidates have more often historically cut into a challenger’s chances at the ballot box.
John A. Tures is a professor of political science at LaGrange College in LaGrange, Ga. His views are his own. He can be reached at jtures@lagrange.edu. His X account is @JohnTures2.
* * *
Methodology note: It is important to note that nearly every election has some sort of third party or independent candidate. To determine the most significant historical cases of third parties and independent candidates, I look at the PBS report “A Third Choice,” covering the 1800s and 1900s. But even PBS doesn’t list all of the viable candidates, missing out on several cases from the 1800s — 1836, 1844, 1848, 1852 — that played out prior to the formation of the modern two-party binary of Democrats and Republicans.
I do not count cases of exclusive intra-party competition (1800, 1824) as having independents or third parties. In addition, the PBS report was written in 2000, so I supplement it with subsequent analysis of elections after the 2000 case. I relied upon Dave Leip’s Atlas of U.S. Presidential Elections. I look at all 17 U.S. presidential elections with a third party or independent challenge and what was the outcome.