New York city is holding a special election for city council, 31st district, on February 19. In New York city, even though elections are partisan, special city council elections are conducted without party nominees. All candidates appear on the ballot with their party label, if they obtain at least 450 valid signatures. Nine candidates filed, but one candidate, Jacques Leandre, then challenged the petitions of six of his opponents. See this story. The story does not explain the basis for the challenge. Leandre, in defense of his action, reminds people that President Obama challenged his opponents’ petitions in 1996 when he first ran for public office. Obama challenged all his opponents off the primary ballot when he was running for State Senate.
Only one of the candidates has been knocked off the ballot. See this story.