Wisconsin’s election commission is set to vote on whether attorney Robert F. Kennedy Jr., and other third-party candidates who could also play spoiler roles, will appear on the swing state’s ballot this November. If confirmed, candidates will be locked into place for the fall vote.

Although Mr. Kennedy does not have a path to the White House in 2024, his campaign has mounted a nationwide ballot access push that has succeeded in 18 states so far, including three seen as competitive: Georgia, Michigan, and North Carolina.

Mr. Kennedy has yet to attain ballot access in some of the most important states in this year’s election, like Wisconsin, Pennsylvania, Arizona, and Nevada. This could change on Tuesday, when Wisconsin’s top election authority votes on whether to grant Mr. Kennedy ballot access.

If Mr. Kennedy is allowed on the ballot, his presence could prove decisive in the state’s results. In 2020, President Biden defeated President Trump in the state by less than 1 point.

The Wisconsin ballot access vote comes as Mr. Kennedy’s effect on the race is changing. Specifically, Mr. Kennedy, who was recruited to run in the Democratic primary by Republican operatives, now appears to be taking more votes from Trump than Vice President Harris. He initially appeared to take more votes from Mr. Biden.

Mr. Kennedy’s vice presidential pick, Nicole Shanahan, blames this change on the Democrats, saying in an interview with a YouTuber, Tom Bilyeu, that they’ve “turned us into a spoiler,” later adding that “it’s not because of the Republican Party taking us out.”

“I don’t think they’re going to let us and, you know, given this, I think we are taking a very serious look at making sure that the people that have corrupted our fair and free democracy do not end up in office in November,” Ms. Shanahan said. “The question is, is, you know, is the risk of a Harris-Walz presidency worth us staying?”

Despite the campaign considering closing up shop in order to help Trump, it may not be allowed to take Mr. Kennedy’s name off ballots. Under this scenario Mr. Kennedy could still play the spoiler in a state like Wisconsin, which was decided by less than a point in 2020.

In Wisconsin, Mr. Kennedy may not be allowed to withdraw his name from the ballot if he is officially confirmed in the commission’s vote. “Any person who files nomination papers and qualifies to appear on the ballot cannot withdraw their name from the ballot after filing,” Wisconsin election law reads.

A Republican think tank, the Heritage Foundation, had threatened to attempt to sue the Democrats when talk of replacing Mr. Biden as the nominee began to circulate after the first presidential debate.

While that threat was largely rhetorical, given that Mr. Biden was only the presumptive Democratic nominee, the statute could be binding for Mr. Kennedy and other minor party nominees after the vote.

Besides Wisconsin, other electorally important states where Mr. Kennedy has attained ballot access also have deadlines coming up soon.

In Georgia, ballots will be finalized by September 17. Once ballots are finalized, a candidate’s name will remain on them even if he or she drops out. According to the secretary of state’s office, prominent notices will be put at polling places if a candidate who has dropped out will appear on the ballot.

In Michigan, there is no public set deadline for when ballots are printed, though any nominee, major or minor party, must be locked in at least 60 days before the election. This year, that day will be September 6. Michigan also says it will supply voters with appropriate information if a candidate drops out between that deadline and Election Day.

In North Carolina, it will be up to the state board of elections to decide whether reprinting ballots is merited in a case where a candidate dies or resigns after ballots are printed. 

Mr. Kennedy’s campaign did not immediately respond to a request for comment from the Sun.