Renault, Nissan and Mitsubishi, on their own, aren’t among the top handful of the world’s auto manufacturers. Together, in a unique alliance, however, they outmatch the sales of giant automakers like Volkswagen.

But the happy confederation has been threatened since its leader, Carlos Ghosn, was arrested on suspicion of financial wrongdoing. He’s no longer in power, and sits in a Tokyo jail cell.

Mr. Ghosn personified the alliance, drawing together disparate auto cultures by the force of his personality. Can it survive without him?

What has happened since Mr. Ghosn was arrested?

A leadership vacuum has opened since Mr. Ghosn’s arrest. Without their longtime leader, Renault and Nissan have blamed each other for trying to tip the balance of power.