Mexico's diplomatic relationships: Mexico has historically maintained strong diplomatic ties with many countries worldwide, including countries in Latin America, Europe, and Asia. These relationships could provide a foundation for Mexico to seek support from the international community in the event of an attack.
The specific circumstances of the attack: The nature and circumstances of the attack would also influence the level of support Mexico would receive. If the attack were unprovoked and violated international law, it is likely that more countries would condemn the attack and support Mexico.
The reaction of the United States: The response of the United States to international condemnation of its actions would also factor into the level of support Mexico receives. If the United States were to disregard international calls for restraint or accountability, it could further galvanize support for Mexico.
Global geopolitical dynamics: The broader geopolitical context, including alliances and rivalries between countries, could also shape the level of support Mexico receives. Factors such as the power dynamics between the United States and other major powers, the role of international organizations, and regional security considerations could all play a role.
Ultimately, the number of countries that would back Mexico in the event of an attack by the United States would depend on various complex and evolving factors, making it difficult to provide a precise prediction.