How Robert F. Kennedy junior’s effect on the election has shifted

Kamala Harris and Donald Trump are sure to be on the ballot in November in all 50 states. Not so all the would-be candidates from third parties. Several such candidates have been facing the distraction of lawsuits that seek to stop them competing in some states.

A Democrat-aligned group has challenged Robert F. Kennedy junior’s right to be on the ballot in Pennsylvania, New York and Illinois, hoping to hobble the idiosyncratic independent candidate. Officials in Wisconsin dismissed an attempt by Democrats to remove Jill Stein, the Green Party candidate, from the ballot in that swing state. The logic of these legal moves is clear: for much of the campaign third-party candidates appeared to be siphoning support from the presumptive Democratic nominee, Joe Biden. But the calculus is shifting—and news that Mr Kennedy may be about to end his campaign, and support Mr Trump, is only the most visible sign.

For Democrats, fear of a third-party “spoiler” looms large, particularly in the six or seven swing states that will decide the election. The last time Ms Stein was on the ballot in Wisconsin, in 2016, she won 31,072 votes—more than Mr Trump’s 22,748-vote margin of victory. In 2000 the Green candidate, Ralph Nader, won nearly 100,000 votes in Florida. After an agonising dispute over “hanging chads”, George W. Bush was judged to have won the state by just 537 votes, and Democrats accused Mr Nader of handing him the presidency.

Third-party candidates contest this framing. They say they draw support from both parties or that their voters would stay at home if they were not on the ballot. But litigation over ballot access shows that Democrats take the threat seriously.

The assumption that third-party candidates hurt Democrats may no longer be correct, though. Polling conducted by YouGov between late May and early July, while Mr Biden was the presumptive Democratic nominee, showed Mr Kennedy winning 3.8% of voters who said they supported Mr. Biden in 2020 (see chart). Ms Stein was winning a further 1.5% and Cornel West, a left-wing independent candidate, another 0.9%. In total, around 7% of Mr Biden’s 2020 voters told YouGov that they planned to opt for a third-party candidate this year. But in YouGov’s polling since Ms Harris became the Democratic nominee, that number has fallen by more than half. Mr Kennedy now wins a larger share of 2020 Trump voters than Biden voters.

This shift is borne out by findings from other polling firms, which ask respondents to choose between multiple candidates as well as between the two main ones. In polls before Mr Biden’s withdrawal, Mr Trump had a 1.3 percentage-point advantage on average in questions that asked about multiple candidates compared with head-to-head polling. With Ms Harris as the Democratic nominee, the effect is reversed: her margin is 0.9 points greater when third-party candidates are included.

Historically, polls have tended to overstate the strength of third parties (see chart). It may be that respondents use them to signal dissatisfaction with their own party. That could help explain why many voters have come back to the Democrats since Ms Harris became the candidate. Third-party candidates will not win a big share of the vote in November, with or without Mr Kennedy on the ballot. True, it takes only a few thousand votes to swing a tight election. But the chances of such minnows handing the White House to Mr Trump have fallen sharply.■

Stay on top of American politics with The US in brief, our daily newsletter with fast analysis of the most important electoral stories, and Checks and Balance, a weekly note from our Lexington columnist that examines the state of American democracy and the issues that matter to voters.