The incorrect statement about the Peninsular War is: "The United States sent an army to support the Spanish and Portuguese efforts against the French." The United States did not send an army to support the Spanish and Portuguese efforts against the French during the Peninsular War. The United States did, however, provide some financial assistance to the Spanish and Portuguese resistance. The other statements are true: Napoleon made his brother Joseph king of Spain, the war lasted from 1808 to 1814, and Napoleon conquered Spain and forced the Spanish king to step down.