Despite the growing literature insisting in showing the advantageous effects that the USMCA has for the Mexican industrial and labor development, this article seeks to offer a critical and historical explanation that helps to understand the causes that led to the momentum of the USMCA and the subordinate role that Mexico has played—and will continue to do so under this new trade arrangement—in the increasingly strengthened process of unequal regional protectionism, which has historically played against Mexico’s domestic industrial development. The main argument in this article claims that the new rules of origin in the USMCA will have a clear and differentiated impact on the automotive firms operating in Mexico, benefiting US firms on the eve of the protection they require in the face of the great technological changes and increasing competition among the global auto firms.