Who was the Mexican president during the Mexican-American War?

The Mexican-American War, which lasted from 1846 to 1848, was a significant conflict between the United States and Mexico primarily over territorial disputes following the annexation of Texas. During this time, Antonio López de Santa Anna served as the president of Mexico and played a crucial role in the war. He was a military leader and had a polarized reputation, often alternating between governance and military leadership.

Santa Anna's leadership during the war was marked by strategic attempts to reclaim lost territory and assert Mexico's sovereignty against what many viewed as American expansionism. His decisions, especially the controversial surrender at the Battle of San Jacinto and subsequent negotiations, significantly influenced the outcomes of the war.

The other choices do not relate to the Mexican-American War timeframe. Diego Rivera was a prominent Mexican painter and muralist active later in the 20th century, long after the war took place. Venustiano Carranza was a key figure in the Mexican Revolution, which occurred well after the events of the Mexican-American War. James K. Polk, while a significant American president during this period and a strong supporter of westward expansion, was not the Mexican president. Therefore, Santa Anna stands out as the relevant figure from Mexico during this conflict.