John C. Fremont
Fremont was not only a military leader, but a politician as well. Prior to the war, he was nominated as the first Republican Party presidential candidate. He also served on the California Senate. Coming from the same party as Lincoln, he was chosen to lead the Union Troops in the very beginning of the war. Since Fremont had control of the Western Department, his focus was on Missouri. Missouri was a border state which John Fremont thought he could reel into the Union. However, his efforts failed, which only made Lincoln worry that Missouri would turn to the Confederate. To ease his worry, Lincoln moved Fremont and his troops to Virginia. In Virginia Fremont came face to face with Stonewall Jackson and was unsuccessful in defeating him. After this loss, another general took command of the troops and Fremont didn't see eye to eye with him. Fremont then decided it was best to ask for resignation, so he was removed from command of the army. Though Fremont's command was short lived, his actions helped inspire other generals to take command, learn from his mistakes, and use the ideas his leadership had given them.