“He’s the most-qualified candidate in the modern-day history of America,” Doug Dern, chair of the Natural Law Party, said in a statement. “We welcome Mr. Kennedy and Ms. Shanahan to the party.”

Kennedy’s campaign alongside running mate Nicole Shanahan is sure to be a factor in the battleground state of Michigan, which former President Donald Trump won in 2016 before losing it to President Joe Biden in 2020.

Shanahan, a wealthy lawyer and entrepreneur who joined Kennedy’s campaign in March, also donated $2 million to the campaign, according to Kennedy’s latest Federal Election Commission filing.

Under federal law, candidates are not subject to contribution limits for their own campaigns.

Since joining the campaign, Shanahan has not appeared publicly with Kennedy. Her running mate said she has spent “the last couple of weeks” visiting constituents, however.

“I talk to Nicole probably two or three times a day,” Kennedy said. “I’m very proud of the stuff she’s been doing. And I look forward to appearing with her in places.”

Biden’s campaign, fearing Kennedy’s potential impact on the election, has built an entire operation focused on attacking him. Trump, meanwhile, has said Kennedy’s campaign is “great for MAGA,” as it could siphon off support from Biden.

The controversial figure, who launched his campaign as a Democrat before switching to Independent, has been waging an uphill battle to gather signatures across all 50 states before their deadlines.

He’s already qualified to appear on the ballot in Utah and has collected enough signatures to run in North Carolina, New Hampshire, Nevada, Idaho, Hawaii, Iowa and Nebraska, according to his campaign.

Kennedy gained prominence for his anti-vaccine views during COVID-19, which have gotten him temporarily banned from several social media platforms. He also has criticized U.S. funding for Ukraine as a “proxy war” against Russia.

Other members of the Kennedy family, meanwhile, plan to publicly endorse Biden at an event later this week.