A significant deterioration in relations between Brazil and Argentina, the two largest members of Mercosur, is unfolding and doesn't appear poised for improvement. The crisis stems from a poor personal relationship between leaders Javier Milei and Luiz Inácio Lula da Silva, escalating into a broader diplomatic conflict. Experts foresee this tension persisting, even worsening, should both presidents secure reelection. This downturn represents one of the most challenging periods for Mercosur in recent years, jeopardizing regional cooperation. The ongoing dispute threatens to destabilize trade and political alliances within the bloc. A prolonged crisis, potentially lasting until 2030, could severely hinder Mercosur’s effectiveness and future prospects.