An obscure New York state election law that has rarely been prosecuted over five decades has been dusted off by Manhattan prosecutors and elevated to a prominent role in Donald Trump’s criminal trial over allegedly falsifying documents related to a hush money payment during the 2016 election campaign.

The law — Section 17-152 of the state’s election code — makes it a misdemeanor for two or more people to “conspire to promote or prevent the election of any person to a public office by unlawful means.” Trump is not being charged under that statute, which apparently has been used only a few times in cases related to state or local elections, though it is a key factor in his case.