After 25 years negotiating with Argentina, Brazil, Paraguay, and Uruguay, the E.U.’s Commission sought to secure passage of the massive trade-deal in the European Council and the Parliament by the end of 2025. Even though the vote is by qualified-majority voting rather than unanimity in both chambers, one state that was against the treaty sought to delay the vote in the Council, which represents states rather than E.U. citizens. The Commission rightly pushed back on the tactic because for one state in opposition to be able to put off a vote is tantamount to having a veto, which a mechanism only for E.U. competencies that are subject to unanimous approval in the Council.
The full essay is at "On the E.U.'s Mercosur Deal."