Disappointed with the convention's peaceful final petition, Spears returned to his home in Bledsoe County, planning to take no part in the upcoming war. Spears was promoted to
brigadier general on March 5, 1862. but Union generals were concerned that the hot-tempered Spears would seek violent retribution against East Tennessee Confederates. General Morgan wrote that Spears had "great energy and courage, but has an idea that war means extermination." In October 1862, Spears and the 25th Brigade were placed under the newly organized
Army of the Cumberland, which was commanded by General
William S. Rosecrans. Rosecrans marched south to Nashville before turning eastward in pursuit of
Braxton Bragg's
Army of Tennessee. In late December, the two armies met at the
Battle of Stones River near
Murfreesboro. As the two armies fought, Spears guided 303 wagons packed with badly needed provisions over muddy roads from Nashville to the frontline, and afterward helped capture a strategic patch of woods known as the "Round Forest" to aid the Union Army's victory. By the spring of 1863, a number of officers under Spears had grown tired of his "tyranny and ungentlemanly conduct," and accused him of incompetence. Upon his return to his unit in August, he ruthlessly reasserted his authority, and threatened to arrest any officer who attempted to resign. In September, twenty-seven officers under his command signed a petition to Rosecrans demanding Spears's removal. At the opening of the
Battle of Chickamauga in September 1863, Spears's unit occupied
Lookout Mountain, overlooking
Chattanooga. He was attacked by a Confederate force led by
Nathan B. Forrest, but was ordered by Rosecrans to abandon the mountain rather than risk capture. Spears staunchly opposed President
Abraham Lincoln's Emancipation Proclamation, and angrily spoke out against it. He allegedly stated, "God damn the Government; let her go to hell, and I'll be found in the ranks fighting her." He was arrested for these statements in February 1864, and subsequently court-martialed. While Spears admitted he disagreed with the Proclamation, he denied making disloyal statements. He was nevertheless found guilty, and ordered removed from command. He was offered an opportunity to resign his commission, but he refused, and was thus dismissed on August 30, 1864. ==Later life and family==