What was the prominent reason the Protestant Reformation weakened Spanish control over its American Empire?

The Protestant Reformation weakened Spanish control over its American Empire primarily by undermining the religious unity that Spain relied upon to assert its authority. As Protestantism spread, it fostered dissent against Catholicism, which was integral to Spanish identity and governance. This fragmentation encouraged local populations in the Americas to question Spanish rule and seek greater autonomy, ultimately diminishing Spain's influence and control over its territories. Additionally, the rise of Protestantism contributed to rivalries with other European powers, particularly England and the Netherlands, which further challenged Spanish dominance in the region.