Billions in ‘dark money’ is influencing US politics. We need disclosure laws | David Sirota and Joel Warner

A donor secretly transferred $1.6bn to a Republican political group. Because of America's lax laws, the donation was never disclosed in any public record or database

This week, the Lever, ProPublica and the New York Times discovered the largest known political advocacy donation in American history. We exposed a reclusive billionaire's secret transfer of $1.6bn to a political group controlled by the Republican operative Leonard Leo, who spearheaded the construction of a conservative supreme court supermajority to end abortion, block government regulations, stymie the fight against climate change and limit voting rights.

This anonymous donation - which flowed to a tax-exempt trust that was never disclosed in any public record or database - was probably completely legal.

David Sirota is an award-winning journalist who founded the investigative news outlet the Lever

Joel Warner is the Lever's managing editor