On the last day of January 2023, in a half-full London courtroom, a lawyer grilled an Irish businessman about his alleged bribes to a former Nigerian government lawyer. The businessman, Brendan Cahill, appeared via video conferencing from Ireland on a TV screen in the corner of the courtroom, as lawyers, journalists and communications teams looked on distractedly.

“Something shady is going on,” said the lawyer at one point.

Little about the atmosphere indicated the stakes: $11 billion, the fate of Nigeria’s economy and a decision that could legitimize the practice of assigning moral responsibility for one country’s corruption inside the courtroom of an entirely different country.

The court case originated in Nigeria in 2008, when the nation’s president at the time, Umaru Musa Yar’Adua, decided to end gas flaring in the Niger Delta. Gas flaring involves the burning of natural gas associated with oil extraction and was responsible for heavily polluting communities in the region. Instead, Yar’Adua instituted a policy of channeling the gas into salvaging Nigeria’s perennially ailing electricity sector.