John Charles Frémont became a popular national figure after leading a series of expeditions intended to survey the Far West in the 1840s. The newly formed Republican Party chose Frémont, an outspoken critic of slavery, as their first presidential candidate in 1856. During the first year of the Civil War, Frémont fervently and controversially attacked slavery and slaveholders in Missouri, culminating in his declaration of martial law, which directed that the property of any individual acting against the United States would be confiscated, including slaves. The order engendered outrage, causing President Lincoln to overturn it and relieve Frémont of his command.