Robert F. Kennedy Jr. is threatening legal action against Nevada over his petition to appear on the ballot as an independent candidate, his campaign said Monday, after CBS News reported that the signatures he had gathered could be invalid because his petition did not include a vice presidential candidate.

The Kennedy campaign claimed that the Democratic Party invented a new rule to invalidate his Nevada signatures. But Nevada’s requirement for a vice presidential candidate to be named in an independent candidate’s petition has been on the books since 1993.

“After successfully collecting all of the signatures we need in Nevada, the DNC Goon Squad and their lackeys in the Nevada Secretary of State’s office are outright inventing a new requirement for the petition with zero legal basis,” said Kennedy ballot access attorney Paul Rossi. “The Nevada statute does not require the VP on the petition. The petition does not even have a field for a VP on it.”

“This corrupt attempt by the Nevada Secretary of State must be enjoined by a federal judge,” Rossi said. “The Kennedy campaign intends to depose the Secretary of State to find out exactly which White House or DNC official concocted this scheme.”

Rossi also linked to an email exchange on Nov. 14 between the campaign and the secretary of state’s office in which the office erroneously said the petition did not require a named running mate.

“Does the vice presidential candidate have to be listed on the petition forms,” a Kennedy ballot access manager asked in the email. “No,” the office staffer replied, referring the campaign to the petition format on page 5 of the state’s petition guide. Rossi also linked to Jan. 9 correspondence from the secretary of state’s office approving Kennedy’s petition.

This differs from Nevada statutes, which say that in an independent candidate’s petition of candidacy, “the person must also designate a nominee for Vice President.”

Documents requested from the Nevada office revealed that Kennedy only named himself, without a running mate, on his candidate petition, in violation of the rules, potentially making the signatures collected in the state void.

The secretary of state’s office acknowledged its staff had misinformed Kennedy.

“Earlier today it was brought to the attention of our office that a Secretary of State employee had provided inaccurate guidance to an independent presidential campaign. This was an error, and will be handled appropriately. In no way was the initial error or subsequent statutory guidance made with intent to benefit or harm any political party or candidate for office,” the office said in a statement to CBS News.

But the office also said that despite the error, it was up to Kennedy’s campaign to follow the statute.

“When a government agency communicates with a member of the public and gives an unclear or incorrect answer to a question, Nevada courts have been clear that the agency is not permitted to honor the employee’s statements if following those statement[s] would be in conflict with the law,” the office said.

Kennedy is so far on the ballot only in Utah, although his campaign says it has collected enough signatures to qualify for the ballot in several other states. Kennedy plans to name his running mate Tuesday, in Oakland.