1856 campaign poster for John C. Frémont. (Image: Public domain)

In 1856, the newly formed Republican Party nominated its first candidate for the American presidency. Hundreds of delegates had gathered in Philadelphia, Pennsylvania, with the aim of sending into the election a candidate who would represent their antislavery position. The men of the Republican Party were drawn from a hodgepodge of political loyalties and backgrounds, and this is what united them: they believed slavery in the United States should be limited—even eliminated. 

There were a handful of men the delegates considered for the nomination, but one man was an early frontrunner—John C. Frémont. The “Pathfinder,” as he was known, had made his name exploring the western territories, and had the greatest name-recognition of the possible candidates. He was also, originally, a Southerner, an unusual trait among early Republicans, and had been openly and vocally opposed to slavery for decades. By the time of the final vote, three of the four other candidates had dropped out, and Frémont won the nomination handily, with 520 votes to his opponent’s 37.

Frémont might have been famous, but for a presidential candidate, he had one unusual stain in his history. Less than a decade earlier, he had been tried and found guilty by the U.S. Army of insubordination and mutiny.

John C. Frémont. (Image: Matthew Brady/J.C. Bottre/Public domain)

Frémont was known for his brashness. Whenever a more powerful person gave him a bit of leeway, he took the opportunity to take as much freedom for himself as possible.

He became famous through a combination of political patronage and daring. As an ambitious young topographer, held back by his birth out of wedlock, Frémont married the daughter of a powerful Washington senator. Then, under commissions acquired through his father-in-law’s influence, Frémont set out west, to map routes to the Rocky Mountains and beyond.

Out in the field, Frémont navigated lands still controlled by native peoples or by Mexico, which governed the area that’s now California, Nevada, Utah, and large parts of Arizona and New Mexico. Frémont’s journeys weren’t just about cartography, though: his father-in-law believed in the Manifest Destiny doctrine, rationalizing expansionism, and those maps he was making were meant to help American pioneers take over the West.

On his third journey, Frémont dropped his role as an explorer and became a conqueror. When he arrived in California, Frémont was working for the Corps of Topographical Engineers, which was organized by the U.S. Army but was supposed to pursue scientific aims—documenting the region in maps and statistics. On his previous journeys, Frémont had studied the hydrology of the Great Basin that stretches across Nevada.

But this third expedition, though purportedly scientific in nature as well, included a group that was much larger and carried more weapons. The Mexican-American war had not yet begun, but as the U.S. and a newly independent Texas discussed a possible union, it was possible to foresee a conflict and a chance for the U.S. to seize still more territory.

Frémont and his men did not sally into California territory as a military force. The area’s Mexican governor initially gave Frémont’s expedition permission to enter, but soon grew suspicious of their motives and forced the group to retreat to Oregon. Yet after receiving orders from D.C.—it’s never been clear exactly what they said—Frémont moved back into California.

The map made from Frémont’s expeditions to the Rockies, Oregon, and California. (Image: LOC 96688041/Public domain)

Back in Mexican territory, Frémont did what he could to wrest control from the authorities without declaring war. His small band of men wasn’t going to take over California on their own. But he did help instigate the Bear Flag rebels—a small group of Americans living in California who revolted against Mexican authorities—to take over Sonoma and form their own government. The rebellion had started.

Not long after, the U.S. Navy arrived on the California coast. The ships had been sent to the Pacific to guard U.S. interests against the British, who, American leaders thought, had their own designs on California. When naval forces found that Frémont had already sparked an American rebellion in the area, they jumped into the battle and started conquering coastal cities. Once the Navy arrived, Frémont dropped all pretense of being a disinterested scientist. He learned that he had been given an military office—he was now a lieutenant general in the Army, and he led his small force of Americans in battles that helped take control of the coast.

The American effort to conquer California wasn’t as organized as it might have been, though. Soon, besides Frémont, there were two major military leaders in California, Commodore Robert Stockton, of the Navy, and General Stephen Kearny, of the Army. Each of these men thought the conquest and governance of California was his responsibility. Neither was inclined to obey the other. Frémont was caught between them—and his efforts to turn the situation to his own advantage went badly. 

Once California was in American hands, the military leaders needed to set up a system to control it—they needed a governor. Commodore Stockton had a claim to the office: his forces had taken control of California before Kearny’s forces had even arrived. Kearny had a claim, too: his orders from the Army were to take over California and install himself as military governor.

Frémont during the Civil War. (Photo: U.S. National Archives and Records Administration/Public domain)

As the hero who had launched the whole campaign and taken control of key cities, including Los Angeles, Frémont had his own designs on the office. At one point, Stockton, Frémont and Kearny all claimed to be governor of California. But when Stockton left the area, he named Frémont military governor, perhaps just to needle Kearny.

Frémont ran with it, and when Kearny tried to order him around, he told the General that, until he was shown good reason, he would continue to follow the authority of Stockton, who had, after all, conquered California. Stockton had made Frémont governor, and so he was governor.

This conflict did not end well for Frémont. Eventually, Kearny, who was 30 years Frémont’s senior, was able to maneuver around the younger man and assert his authority over the new territory. Frémont reluctantly agreed to travel back east, under Kearny’s command.

By the time he reached Missouri, Frémont had been essentially taken prisoner, and in St. Louis, the General filed formal charges against the upstart explorer. Frémont was taken to D.C. to stand trial before a military court, for mutiny, insubordination and other offenses. If he was found guilty, the usual sentence for these charges was death.

Frémont seemed not to be as troubled by his situation as he ought to be. Reunited with his wife, they even spent one night driving “in the moonlight out to the school in Georgetown and looked up at the back window where the Colonel’s first love letter had come up hidden in a basket of laundry,” his wife later wrote. He mounted a thorough defense against Kearny’s charges, arguing that he was obeying orders—just not Kearny’s orders—and that the confusion could be traced all the way back to conflicting commissions from the Navy and Army in D.C.

The military men who sat in judgement did not buy it: Frémont was found guilty on all counts. But President Polk commuted his sentence, in part because of the influence of Frémont’s father-in-law, but also out of a desire to avoid a greater scandal. Polk ordered Frémont back to his unit, but the mapmaker was no longer interested in serving in the Army. He quit and returned as a private citizen to California, where gold had been found on a property he owned.

Just a few years after being tried for mutiny, Frémont was rich, and when California became a state, he was voted in as one of its first senators. He didn’t hold the position for long—he lost it because of his anti-slavery stance. But that made him an ideal candidate for the new Republican Party, which ran him under the slogan: Free Soil, Free Men, Frémont.