On Jan. 31, 1848, U.S. Army officer John C. Frémont was court-martialed for mutiny for failing to obey the orders of a superior officer in California during the Mexican-American War.

John Charles Frémont had been born in Georgia in 1813, and in the 1830s, he joined the Army as an engineer and mapmaker. In 1841, he married Jessie Benton, the daughter of Missouri Senator Thomas Hart Benton, nicknamed “Old Bullion.” He shared his father-in-law's belief in Manifest Destiny, the idea that the Untied States was destined to rule the North American continent from the Atlantic to the Pacific oceans.

Not long after his marriage, Frémont began to lead a series of expeditions to the West, where he earned his reputation as a frontiersman and a mapmaker. Soon, he earned the nickname “Pathfinder of the West,” and his descriptions of Utah and the Salt Lake Valley influenced Brigham Young and his Mormon followers in choosing the region for settlement in 1848.

As war appeared to be on the horizon between Mexico and the United States in 1845, Frémont was ordered to set out from St. Louis toward California. By December, Frémont arrived in Monterey, California, with 62 men and soon met with Jose Castro, the Mexican military governor of Alto California, a region that encompassed much of the present day states of California, Nevada and Utah. Frémont assured Castro of his peaceful intentions and promised the Mexican his stay in California was only temporary.

Frémont also met with the American consul in the city, Thomas Larkin. Not long after Frémont's departure for the U.S. Oregon territory to the north, a marine officer arrived in Monterey with orders for both Larkin and Frémont. While Larkin was ordered to spread the word that rebels to Mexican authority would be welcomed by the United States should war break out, Frémont interpreted his orders to mean that in the event of war, he was empowered by the president to conquer California. This cannot be verified, however, as the exact orders are no longer extant.

In the book, “What Hath God Wrought: The Transformation of America, 1815-1848,” historian Daniel Walker Howe wrote: “In 1846, the population of Alto California numbered about 15,000, not counting the much larger number of Native Americans. … Only about 800 of these people were of U.S. origin, most of them very recent arrivals. With the reckless daring that characterized his whole life, young Captain Frémont expected to make a successful revolution based on those 800.”

In June 1846, a handful of California rebels joined Frémont in a revolution that overthrew Spanish rule in Sonoma, California. The rebels hoisted a flag featuring a bear upon it, and on July 4 engaged in Independence Day celebrations, marking the independence of the United States from Britain and their own independence from Mexico. A few days later, the U.S. Navy conquered Monterey without loss of life to either side.

In September, however, the Mexicans revolted against the U.S. forces occupying the region. When Frémont's rebels and U.S. forces had taken the key cities from the Mexicans, the Mexican authorities had mostly fled, hoping to save their skins. The pro-Mexican revolution, however, was quite different. The American authorities were there to stay, and several insurgent battles took place in which both sides saw their share of casualties. Several key cities such as Santa Barbara and San Diego were claimed by the Mexican rebels.

While Frémont and Commodore Robert Stockton fought the Mexicans, they awaited the arrival of Brigadier Gen. Stephen Watts Kearny whose force was marching from New Mexico. Kearny expected the Mexican revolutionaries to fold with his first attack, but it was not to be. The Mexican horsemen dealt a serious blow to Kearny's own cavalry, and Stockton had to rescue Kearny from defeat. Together, however, they proved more formidable, and they were able to deal defeat to the revolutionaries at Los Angeles on Jan. 8, 1847.

Frémont arrived a few days later, bolstering the U.S. forces considerably. The Mexican revolutionaries now had no hope of a military solution, and Frémont signed a peace treaty with them granting them rights as American citizens, without the approval of his superiors. Frémont and Stockton soon made common cause, but friction between Stockton and Kearny grew in the wake of their victory at Los Angeles.

What happened next would ultimately lead to problems for Frémont and even for President James K. Polk. Stockton returned to his ships and prepared to set sail for Mazatlán. First, however, he appointed Frémont “governor and commander-in-chief of the territory of California until the president of the United States shall otherwise direct.” Kearny, however, believed that only he had authority to make decisions in California. He outranked Frémont and had interpreted his own orders as such that only he had supreme authority to act in the recently won territory.

Kearny began to issue orders that Frémont ignored. The two men began butting heads, and in mid-February, Kearny received new orders from Winfield Scott, the commanding general of the Army. Kearny was to exercise the authority of civil governor.

Polk didn't learn about the controversy until April but soon satisfied himself that Kearny had acted correctly. The problem, however, was the political influence wielded by Frémont's father-in-law, Senator Benton. Benton had long been campaigning for a top command position within the Army during the war, and Polk had to use all of his finesse to deny the aging politician his wish. Now, Benton was pressuring the president to help clear his son-in-law's name.

Frémont's wife appeared at the White House with frontiersman and family friend Kit Carson to persuade the president to act on the officer's behalf, but Polk took a neutral tone with them. He wrote later in his diary, “Mrs. Frémont seemed anxious to elicit from me some expression of approbation of her husband's conduct, but I evaded making any. … I consider that Colonel Frémont was greatly in the wrong when he refused to obey the orders issued to him by General Kearny.”

Benton continued to pressure the president, a fellow Democrat, telling him that it should be a matter for the Senate, not the military, to investigate. It didn't help matters when Benton's son haughtily demanded that the president appoint him a lieutenant in the Army, and when Polk refused on the grounds that preference must be given to enlisted men with war experience, the young man stormed out of the Oval Office.

Frémont's court-martial finally began on Nov. 2, 1847. The Washington Arsenal building housed the proceedings, where 13 high-ranking officers would decide Frémont's fate. Benton, along with another son-in-law, William Carey Jones, represented Frémont and debated the language of Kearny's original orders, suggesting vagueness and inexact instructions.

The court-martial concluded on Jan. 31, 1848. The officers found Frémont guilty of mutiny, disobedience of orders, insubordination and more. The sentence called for Frémont to be drummed out of the Army, though most of the officers favored clemency. In the book, “Polk: The Man Who Transformed the Presidency and America,” historian Walter R. Borneman wrote:

“Now the fate of Old Bullion's son-in-law lay with the president. Polk had made it quite clear that he would do his duty without regard to Benton's friendship, but he was also one to appreciate results. Rightly or wrongly, Frémont had had a hand in securing California and accomplishing one of the key goals of Polk's presidency. What would the president do?”

Polk hoped to mollify Benton by upholding the court's ruling, but also accepting its recommendation for clemency. Therefore, Polk ordered Frémont to report to his regiment, but Frémont refused. He would not continue to serve unless the court's ruling was overturned. When Polk said nothing more on the case, Frémont resigned and took his wife west to California. The political cooperation that Polk had always enjoyed with Benton was gone. The two men were now enemies.

Frémont eventually ran as the first Republican presidential candidate in 1856, on an anti-slavery platform, but lost to the man who had been Polk's secretary of state, James Buchanan.

Cody K. Carlson holds a master's in history from the University of Utah and has taught at SLCC. He is currently a salesman at Doug Smith Subaru in American Fork. Email: ckcarlson76@gmail.com