Political career and service in the American Civil War
François was excluded from continuing a career in the Second Republic's navy. So in 1851, he announced his candidacy for the French presidential election to be held in 1852, hoping to pave the way for an eventual restoration of the monarchy. His plan to become a second "Prince-President" was preempted by the 2 December 1851 coup by which the first "Prince-President", Louis-Napoléon Bonaparte, effected his own ascension to the throne.
In 1861, upon the outbreak of the American Civil War, he went to the United States, and placed the services of his son and two of his nephews at the disposal of the government. President Lincoln appointed him and his nephews to the staff of Major General George B. McClellan. In June 1862, disagreements with the US position towards Mexico caused the prince to withdraw from the Union forces, and he returned to Europe.
With the overthrow of the Second Empire in 1870, François returned to France, only to be promptly expelled by the Government of National Defense. Returning incognito, he joined the army of general Louis d'Aurelle de Paladines, under the assumed name of "Colonel Lutherod", fought bravely in Orléans, and afterwards, making public his identity, formally sought permission to serve the French army. Gambetta, however, arrested him and sent him back to England.
In the elections of 1871 to the National Assembly, the prince was elected to sit for the Haute-Marne, the department of his former principality. By an arrangement with Adolphe Thiers, however, the prince did not take his seat until the latter had been chosen president of the provisional republic.
