In 2020, the Constitutional Court struck down a constitutional amendment, preventing Congress from regulating a matter that, according to the Constitution, can only be initiated by the president. The Court defended a presidential model based on a Constitution that a Constitutional Convention will soon replace. It tried to defend a “lame duck” Constitution. In 2021, a similar case arrived at the Court but, this time, the Court decided not to hear it. This essay makes two arguments: First, the cases bring light to a democratic but unusual way to justify the UCAD. Instead of preserving the democratic minimum core, the UCAD can help to stabilize political processes defending the president’s legislative power. Second, as a weak and divided Court sustained the first decision, and stronger electoral pressures influenced the second case, the Court’s doctrine can fail. Using the doctrine to defend a “lame duck” constitution brings new challenges that the literature has yet to explore.