Independent presidential candidate Robert F. Kennedy Jr. s bid to appear on the ballot in Nevada could be in jeopardy after he failed to include a potential vice president on his filing documents.

CBS first reported the potential snag on Monday, just a day before Kennedy is expected to announce his running mate on Tuesday at an event in Oakland, California. Nevadas guidelines for presidential candidates require independent petitions to include the names of both a presidential and vice presidential pick before they begin collecting signatures in order for them to be valid. The news outlet confirmed those rules with the Nevada secretary of states office.

CBS obtained documents from the office that only display Kennedys name, which would appear to be a violation of state statutes.