Marianne Williamson, the self-help author, on Tuesday attempted to revive her on-again, off-again long-shot candidacy for the Democratic presidential nomination by calling on the party to reopen the competition during its August convention in Chicago.
Ms. Williamson said in a statement that President Biden’s widely criticized debate performance on Thursday had made it clear that it was time for another Democrat to lead the ticket against former President Donald J. Trump in the November election.
“The nominating process for the Democratic Party needs to begin again,” Ms. Williamson said. “We need to recalibrate, and we need to do so quickly.”
The Democratic National Committee did not immediately respond to a request for comment.
A shift to an open or brokered convention would be highly unusual at this stage of an election cycle. It has been more than 40 years since a major party went into its convention without a clear indication of who would lead its ticket.
Mr. Biden clinched the Democratic nomination in March with a series of resounding primary victories over a handful of nominal challengers, including Ms. Williamson, who suspended her campaign in early February. Later that month, she announced that she was re-entering the race after finishing third in Michigan’s primary, where she received 3 percent of the vote.
In calling for Democrats to change to an open convention, she said on Tuesday that she had combined to receive more than a half-million votes in primary contests.
“It is imperative that the new process not be manipulated by party and media elites,” Ms. Williamson said. “The search for a new candidate must be not directed by behind-the-scenes players, but rather must be a genuinely democratic process.”