Kansas City, Missouri — At his campaign events, Robert F. Kennedy Jr. isn't just making his pitch for the presidency — he's also asking voters to put him on the ballot in their states, a steep hurdle that must be cleared by independent candidates.

At a recent rally in Kansas City, Missouri, Kennedy asked the crowd of about 300 voters for help. The state requires independent candidates to collect 10,000 signatures by July 29 to appear on the 2024 general election presidential ballot.

"I need you to help me," Kennedy said. "You know, in this state, Democrats and Republicans both get on the ballot for free. I need to work for it."

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The requirements for ballot access for candidates who are not the Democratic or Republican nominees vary widely from state to state, and the first deadlines are in early March, for North Carolina and Utah. Utah originally required independent candidates to file by Jan. 8, 2024, but earlier this month — soon after Kennedy filed a lawsuit against the state — it changed the date to March 5.

Ed Rollins, the campaign manager for Ross Perot, who ran for president as an independent in 1992 and as the Reform Party nominee in 1996, said getting on the ballot in every state was the hardest part of Perot's 1992 bid. 

"It's a very difficult process…to be an independent candidate, and qualify for the ballot it takes a real massive grassroots effort," Rollins said. 

Perot spent millions on ballot access, and even though he succeeded in making it onto the ballot in all 50 states, he did not win any of them. 

"It was a massive cost, and anybody today that basically wanted to do that is to have upfront money and be prepared to go forth, challenge the establishment in most places," Rollins said. 

In an interview with NewsNation last week, Kennedy estimated he'd need "about a million signatures and navigating" rules and requirements to make it onto the ballot in all the states and the District of Columbia. Some states require just a few thousand signatures, he said, but others "deliberately make it very, very difficult to get on, and you have to have the signatures notarized, and you have to get them from every county, and you have to do it in a very, very short period of time." But he claimed he has a massive army of volunteers — 250,000 — that will be helping him. His campaign told CBS News that number is closer to 45,000 volunteers.

Without this volunteer help, he said that paid signature gatherers would charge about $15 per signature, so for the signatures alone, ballot access would usually cost as much as $15 million. 

However, Kennedy's ballot access drive will also be heavily underwritten by the super PAC supporting him, American Values 2024. In December, the super PAC announced it would be investing $10 million to $15 million to put him on the ballot in at least 10 states, including Arizona, California, Colorado, Georgia, Illinois, Indiana, Michigan, Nevada, New York, and Texas. The super PAC told CBS News part of this investment will be used for a team of lawyers to navigate the guidelines and requirements. 

Kennedy press secretary Stefanie Spear told CBS News expressed confidence about his ballot access prospects. 

"We've begun signature collection in all open states and you know we're confident that Mr. Kennedy can get the 270 electoral votes and win the White House," Spear said. In some states signatures must be collected within a certain window of time. 

"We're making our schedule," she said, adding that she expected "that we can be successful at collecting signatures in every state and meeting all the different state guidelines in order to get him on every ballot in 50 states."

Utah just pushed its deadline to obtain 1,000 signatures from Jan. 8 to March 5 after Kennedy filed a lawsuit last week that called the original date "unconstitutionally" restrictive. 

"We're going to have to probably fight legal battles from out of the states, but we're ready to do that," he said in response to a question from CBS News.

College student Jacob Halphin, 25, signed Kennedy's petition for the Missouri ballot at Wednesday's rally and says he would consider an independent candidate. 

"I'm completely open to anyone, just preferably not Biden, or Trump, but not necessarily Kennedy," Halphin told CBS News.

"He deserves to be on the ballot if he's going through this much trouble and it's created this much of a wave," Halphin said.

Kennedy's in-person appeal to voters in Missouri underscores the state's potential openness to independent candidates. The state has backed Republicans for the presidency in every election for decades — except in 1992 and 1996 — the years that Perot ran. Bill Clinton won in both of those years. Perot received 22% of the vote in Missouri in 1992, and George H.W. Bush won 34% — the worst performance for a Republican in the state since 1860. 

University of Missouri political science professor Elizabeth Vonnahme says there is an "appetite for something besides Trump and Biden."

"Kansas City is a good spot in the sense that it can appeal to folks on the Missouri side and the Kansas side who might be disaffected by both the Democrats and the Republicans," Vonnahme said. "There's a significant number of people like that, who would be willing to come to a rally and are willing to at least hear out an independent candidate for president."

Patrick Marsh, who crossed the state border from Kansas for Kennedy's rally, says the signature-gathering effort hasn't begun there, but he's ready to sign the petition to put Kennedy on the ballot in his state. 

"We want him to be on the ballot, but I think he'll get it done," Marsh said, adding that Kennedy is "the only person I'm voting for. I'm not considering anybody else."

Cristina Corujo

Cristina Corujo is a digital journalist covering politics at CBS News. Cristina previously worked at ABC News Digital producing video content and writing stories for its website. Her work can also be found in the Washington Post, NBC and NY1.