This is a guest post by Peter A. Wallner, author of a two-volume biography of President Franklin Pierce consisting of “Franklin Pierce: New Hampshire’s Favorite Son” (2004) and “Franklin Pierce: Martyr for the Union” (2007).

It is often forgotten that Franklin Pierce, the 14th president of the United States, was also a brigadier general in the Mexican War (1846–48) who commanded troops under General Winfield Scott in the campaign around Mexico City. Pierce was a political general, appointed by President James K. Polk, and served directly under Polk’s close friend General Gideon Pillow, while maintaining a relatively apolitical stance toward the Whig General Scott.

For the only time in his life, Pierce kept a diary, in which he recorded his experiences in Mexico. He expected at some future time to pass the diary along to his only surviving son, Benny, but the latter died in a train wreck prior to Pierce’s presidential inauguration in 1853.

Scott was already near Mexico City when Pierce and his 2,500-man brigade reached Vera Cruz. After acquiring nearly a thousand mules to pull the wagons full of supplies and funds that Scott so desperately needed to carry out his campaign, Pierce and his men set off for the 150-mile trek inland to meet up with Scott. Along the way, Pierce and his brigade were attacked six times by guerillas, who at one point blew up a stone bridge across the Plan del Rio. This required Pierce and his men to build quickly a new wooden bridge, prompting Pierce to write in his diary that it was absurd for the Mexicans to think that they could “play such a trick upon Yankees.” (See Pierce diary entry of July 22, 1847).

On another occasion, Pierce’s suspicions were raised by the friendly greeting he received in the town of Jalapa. Sensing something was wrong, Pierce withdrew from the town, later learning that it was a hotbed of guerilla activity. This caused Pierce to reflect in his diary on the utility of a limited war strategy in Mexico. “Perhaps a peace can be conquered by our present system of operations and policy. If so, we have made a grand leap in civilization, we will astonish the world . . . we will make wars to cease . . . because if we can conquer a peace in this way we can conquer it better without arms than with them.” While Pierce accepted that the United States was on a “mission of civilization and humanity,” he believed that “human butchery” by Mexican combatants made this impossible. He concluded that the best answer was “war to the knife and the knife to the hilt.” (See Pierce diary entry of July 25, 1847)

The next day Pierce regretted what he had written, noting that the purpose of the diary was simply to state the facts so that he could remember them better at some future time. The diary entry also reminded him of his friend Samuel E. Coues of Portsmouth, New Hampshire, who wanted all nations to outlaw war. He concluded that as a general he was responsible for prosecuting the war since “such a course would more speedily lead to peace.” (See Pierce diary entry of July 26, 1847). The diary ends on July 30, 1847, when Pierce’s brigade joined up with Scott’s army.

The remainder of Pierce’s time in Mexico was more controversial. On August 19, during the Battle of Contreras, Pierce was thrown from his horse, which landed on his knee. Though visibly suffering from his injuries, Pierce insisted on participating in the Battle of Churubusco the next day. At one point, he had to dismount his horse to lead it across a stream, and the pain in his knee caused him to faint.

This became a campaign issue in the 1852 presidential election when the “fainting General” charge was leveled against Pierce as an indication that he was a coward.

The vast majority of Mexican War officers, however, supported the Democratic contender Pierce in 1852 against their former commanding general Winfield Scott, the Whig candidate. Among those who supported Pierce were volunteer officers including Jefferson Davis, Caleb Cushing and Gideon Pillow. In fact, Cushing and Pillow met with Pierce twice in the months leading up to the Democratic convention to urge him to run for president. Also supporting Pierce were professional officers such as Robert E. Lee, George B. McClellan, and P. G. T. Beauregard. It is unlikely that such men would have supported a candidate guilty of military cowardice.

In any case, the accusation did not prevent Pierce from winning the election.