Donald Trump will speak at the Libertarian Party’s convention at the Columbia District later this month — signaling how worried Mr. Trump must be about third-party “spoilers” and independent presidential candidate Robert F. Kennedy Jr.’s appeal to libertarians.

Mr. Trump lost several swing states, including Arizona, Wisconsin, and Georgia, in 2020 by fewer votes than those cast for Libertarian Party candidate, Jo Jorgenson. Polls indicate the 2024 election will be as close, with third-party candidates potentially determining the winner in key swing states.

Mr. Kennedy ruled out seeking the Libertarian Party’s presidential nomination just two weeks ago, but he has courted the libertarian vote since he entered the race as a Democrat one year ago. He has made the rounds of libertarian podcasts and spoke at gatherings like PorcFest, Freedom Fest, and the Libertarian Party of California’s convention at Costa Mesa in February.

The Libertarian Party’s chairwoman, Angela McArdle, says she extended an invitation to speak at the party’s convention to both Mr. Trump and President Biden. Mr. Trump’s acceptance is a sign he is taking third-party voters seriously. He’s also likely taking a page from his former Republican primary opponent-turned-advisor, Vivek Ramaswamy, who actively courted the liberty vote.

“Libertarians are some of the most independent and thoughtful thinkers in our country, and I am honored to join them in Washington DC,” Mr. Trump said in a statement Wednesday. “If Libertarians join me and the Republican Party, where we have many Libertarian views, the election won’t even be close.”

While much of the focus on third party candidates this year has centered on the threat to Mr. Biden, recent polls that show Mr. Kennedy pulling more votes from Mr. Trump are sounding alarm bells in the Trump orbit. Mr. Trump has stepped up his attacks on Mr. Kennedy, calling him a Democrat “plant,” far-left, and a “wasted protest vote.”

The announcement Wednesday that Mr. Trump will be speaking at the party’s convention was greeted in typical Libertarian fashion: with fights online about “MAGA infiltration” of the party and debates about libertarian principle versus political relevance. In May 2022, a paleo libertarian faction called the Mises Caucus took over leadership of the party. Those who oppose them call this faction a MAGA front. 

“It’s just confirmation that the Mises Caucus was a MAGA operation from the beginning,” a former chairman of the Libertarian Party, Nicholas Sarwark, tells the Sun. “The Mises Caucus is a stalking horse kind of operation to assist Donald Trump in not losing the 2024 presidential election in the same way he lost the 2020 presidential election.”

“You can’t be an independent political party and kiss the ass of one of the other two,” Mr. Sarwark says. “That’s why the Greens have collapsed,” he says of the Green Party. 

“If libertarians are to succeed at moving politics in a more liberty-oriented direction, then we must build our own brand as far away from Donald Trump as possible,” a former Republican-turned-Libertarian congressman, Justin Amash, who is now running for the United States Senate from Michigan as a Republican, posted to X.

“If Donald Trump comes to our convention, he will be met with a chorus of boos,” a Libertarian Party presidential candidate, Chase Oliver, tells the Sun.

Ms. McArdle, though, says party members should take Mr. Trump coming to speak to them as a win and a way to bring “the message of liberty” to a wider audience. She said the same about Mr. Kennedy when he courted the party.

“For 50 years, we’ve been trying to get our candidates on the main stage with major party POTUS candidates and we’ve finally succeeded in bringing one to our stage,” Ms. McArdle said in a statement.

“Is this a secret plot to make Trump our candidate? No. Are our candidates doing a head to head debate with him? No. They are doing their debate first, then he is speaking. (Take the W.),” Ms. McArdle posted to X.

“I know there are some libertarians who have a severe allergy to relevance, but it is undeniably a great thing that Trump is speaking at the Libertarian Party National Convention,” comedian and podcaster, Dave Smith, posted to X. “This isn’t an endorsement of Trump, it’s an endorsement of relevance and a desire to engage with the real world.”

“If the LP is actually able to create a Libertarians vs. Trump moment, it would be an absolute W. There’s a huge vacuum of intelligence on the right, as well as a vacuum of opposition to Trump on the right, and it would be great to have the LP be in that space,” a Libertarian Party of New Hampshire delegate, Jeremy Kauffman, tells the Sun. 

“Libertarians are such open-minded people,” he adds, “that we’ll even discuss our ideas with far-left gun-grabbing money-printing pro-lockdown socialists like Donald Trump.”